EARTHY, ALKALINE AND METALLIC SULPHURETS.
The sulphurets exhibit a very important class of combinations of two
elements. Many of the metals are found chiefly in the state of native
sulphurets, and are extracted by particular processes. Artificial
combinations of sulphur and the metals, and of sulphur and the earths
and alkalies are commonly practised, and are found useful in chemical
investigations. The alkaline and earthy sulphurets will scarcely be
allowed perhaps to be combinations of _two elements_ only; but their
analogy with the other compounds is such as to induce us to treat of
them under this head, especially as they are agents occasionally in
the formation of metallic sulphurets, and these cannot be so well
understood without some knowledge of the other. For like reasons
the compounds of three elements, sulphur, metal, and oxygen, called
sulphuretted oxides, and sulphuretted sulphites, and those of four
elements, sulphur, metal, oxygen and hydrogen, called hydrosulphurets,
may be considered at the same time, having an intimate relation with
the sulphurets strictly so called, or the compounds formed with sulphur
and the undecompounded bodies.
Sulphur may be combined with the earths, alkalies and metals, by heat,
of various degrees according to the nature of the subjects. The union
is attended in many cases with a glowing ignition, indicating the
evolution of heat. The metallic oxides and sulphur when heated together
commonly produce a sulphuret of the metal, whilst the oxygen escapes
with part of the redundant sulphur in the form of sulphurous acid, and
the rest of the sulphur sublimes.
In the humid way sulphur may be combined with earths, alkalies, and
metals, by means of sulphuretted hydrogen, hydrosulphurets (that is,
sulphuretted hydrogen united to other alkaline or earthy bases), and
hydroguretted sulphurets (a name given to certain earthy and alkaline
sulphurets formed mostly by boiling mixtures of the respective bases
and sulphur in water.) The sulphuretted hydrogen may be used in
this state of gas or combined with water; the hydrosulphurets and
hydroguretted sulphurets are best applied in their watery solutions.
The metals are to be used in this case in the state of salts, that is,
oxides united to acids, and in solution; or their oxides may in some
instances be precipitated previously to the addition of the sulphur
compound; the alkalies and earths are sometimes directly sulphurized in
the state of hydrates, and at other times by double affinity, in the
state of salts or combined with acids. The phenomena in the case of
sulphurets formed in the humid way, are various and often complicated,
and the true results are not always to be obtained without considerable
difficulty and uncertainty.
1. _Sulphurets of lime._
When pounded lime and sulphur are mixed together, and heated in a
crucible scarcely any union takes place; the sulphur sublimes or burns
away and leaves the lime unaltered. If for lime we substitute carbonate
of lime, it also remains unaltered. But if hydrate of lime and sulphur
are heated together in equal weights, the hydrate is decomposed, and
the lime unites to a portion of the sulphur, whilst the excess of
sulphur sublimes or burns and escapes at a low red heat. The residue,
about 60 per cent. of the original weight, is a yellowish white powder,
composed of sulphur and lime. If this be again treated with sulphur
and heated, it undergoes no material change; the last sulphur entirely
escaping, leaves the sulphuret unaltered, and hence shews that it must
be a true chemical compound.
Now if 32 parts hydrate of lime, which consist of 24 lime and 8 water,
be mixed with 32 sulphur and heated as above, they will yield 38
parts sulphuret, which must be composed of 24 lime and 14 sulphur,
or sulphur and water; but it appears from the analysis hereafter to
be given, that the whole of this last part is sulphur; therefore the
compound is formed of 1 atom of lime, and 1 of sulphur, and is the
_protosulphuret_ of lime.
When 32 parts of common hydrate of lime and 56 sulphur, are boiled
together in 1000 parts water for half an hour, or more, occasionally
adding water to supply the waste, a fine yellow liquid is obtained,
with a few grains of residuum containing both lime and sulphur nearly
in the original proportion with a few grains of alumine. This liquid
of course contains in solution, a combination of 1 atom of lime, or
perhaps hydrate of lime, and 4 atoms of sulphur; and may therefore
be called a _quadrisulphuret_ of lime. If more sulphur or lime
than the above proportion be used, the surplus will remain in the
residuum uncombined, shewing that by this process no other than a
quadrisulphuret can be formed. A similar solution may be obtained in
cold water by frequent agitation; but it is much slower in producing
the effect. The strength of liquid quadrisulphuret depends upon the
relative quantity of the ingredients. I have boiled it down till the
water was only 5 times the other materials, which appears to be its
maximum strength in the common temperature; its specific gravity was
1.146; but in general I have used it of less than 1.07 density. It
may be proper to remark here that I find the decimals multiplied by
4 express very nearly the number of grains of lime in 1000 grains
measures of the solution, and multiplied by 9 those of the sulphur;
on this account a solution of the sp. gravity 1.06 facilitates the
calculations, as 100 measures of it contain 2.4 grains of lime, and 5.4
or 5.6 of sulphur nearly.
It is rather surprising that no bisulphuret nor trisulphuret of lime
should be formed this way. One would suppose that the sulphuret of
lime in its progressive changes would have passed through the forms of
bisulphuret, &c. till it had obtained its maximum of sulphur when that
was in excess; but, as has been observed, the quadrisulphuret is the
only one formed, whatever may be the proportions of the ingredients.
I imagine the reason to be, that the sulphur has to decompose the
hydrate of lime, and that no fewer than 4 atoms of sulphur are adequate
to that effect; it is known that water adheres so strongly to lime
as to require a red heat to separate it. When therefore we mix lime
water with quadrisulphuret of lime, it must be considered as a mere
mixture of the two, and that the lime does not divide the sulphur
equally. Consistently with this reasoning, whenever the lime is in
excess in forming quadrisulphuret of lime, we ought to consider the
liquid solution as _lime water_ holding quadrisulphuret of lime. This
distinction will be of some importance when the solution is weak,
because then the lime in the lime water will be considerable, compared
with the lime combined with sulphur.
1. _Protosulphuret._ The properties of this compound are;--about 1
grain is soluble in 1000 water; this water, as well as the powder
itself, tastes like the white of an egg; salts of lead are thrown
down black by the solution; weak nitric and muriatic acids dissolve
the lime, and leave the sulphur; 100 parts of test acid require 19
of the powder, and yield 7 of sulphur; indicating the compound to be
12 lime and 7 sulphur. The same conclusion may be obtained by means
of a solution of lead; if water containing 1.9 grains of the powder
be precipitated by nitrate of lead, it will require 7 grains of the
salt = 2.2 acid and 4.8 oxide, or 4.5 lead, and about 5 or 5½ grains
of sulphuret of lead will be formed, and the liquid will contain 3.4
grains of neutral nitrate of lime.
2. _Quadrisulphuret._ This combination has been long known, and
some of its properties observed; but I have not found in authors any
determination of its proportions. It is of a beautiful yellow or orange
colour, and 1 grain imparts very sensible colour to 1000 of water; it
has a disagreeable bitter taste; when evaporated down, it crystallizes
or rather perhaps solidifies into a yellowish mass; but its properties
are affected by the process from the acquisition of oxygen. This
mass when dried, burns with a blue flame and loses 40 per cent.; the
remainder is a white powder, a mixture of sulphite and protosulphuret
of lime. Liquid quadrisulphuret exposed to the atmosphere soon becomes
covered with a white film which arises from the sulphur displaced by
oxygen gas; this film being broken subsides, and another is formed,
and so on successively till at length the acquisition of oxygen
ceases with the deposition of sulphur, and the liquid remains quite
colourless. It is intensely bitter, and contains lime, sulphur and
oxygen in proportions to be presently determined. This colourless
liquor undergoes a gradual change by being kept for years in a bottle
with a common cork; a deposition of some sulphur and sulphate of lime
takes place, but whether from a further acquisition of oxygen gas or
from some internal chemical action, I have not had an opportunity of
observing.
From the above observations it is obvious that to form _pure_
quadrisulphuret of lime the atmospheric air should be excluded, as the
agitation by ebullition would promote the oxidizement of the compound.
I mixed 168 grains of sublimed sulphur with 96 hydrate of lime, which
by previous trials I had found to consist of 70 lime including 2 or
3 grains of alumine, and 26 water; the mixture was put into a small
florence flask, which was then filled with water up to the neck and
loosely corked. This was immersed in a pan of water and boiled for 2 or
3 hours, the flask was continually turned round to agitate the mixture
and promote the solution. After the undissolved part had subsided the
clear liquor was decanted and found to be 2800 grain measures of the
sp. gr. 1.056; the residuum moderately dried weighed 34 grains; it
was found to contain 8 of lime and alumine, and 25 of sulphur. Hence
the liquid contained 62 lime and 143 sulphur, or 2.2 lime and 5.1
sulphur per cent.; that is, after the rate of 24 lime to 56 sulphur,
or 1 atom of lime to 4 of sulphur, and its weight = 80, the atom of
sulphur being supposed 14. Here then we have a synthetic proof of the
composition being a quadrisulphuret. Innumerable other experiments,
though made with less rigid accuracy, had convinced me that the liquid
is essentially the same whatever the proportions of the ingredients,
and that the residuum only varies in such cases.
I have made many experiments occasionally since 1805, on the quantities
of oxygen absorbed and sulphur deposited by quadrisulphuret of lime.
They all concur in establishing the same conclusion; namely, that each
atom of the compound takes 2 of oxygen and deposits 2 of sulphur,
in its transformation from the yellow to the colourless state. For
instance, 100 measures of the above 1.056 took 900 of oxygen gas = 1.22
grains, and let fall 2 grains of sulphur, besides a small portion which
adhered to the bottle, which was estimated at a few tenths of a grain.
The method is to put 100 measures into a graduated and well stoppered
bottle filled with oxygen; to agitate briskly for half an hour,
occasionally opening the stopper a little under water to admit its
entrance into the place of the oxygen absorbed. Whenever the agitation
has been continued for five minutes without any sensible increase in
absorption, and the liquor, after standing to let the sulphur subside,
appears colourless, the experiment is finished. This new combination
then consists of 1 atom lime, 2 sulphur, and 2 oxygen = 66; it will be
necessary to give it a name: I propose calling it sulphuretted sulphite
of lime, as it is an atom of sulphur united to sulphite of lime; and
the rather, as it will appear in the sequel that other neutral salts
do combine occasionally with an atom of sulphur. This sulphuretted
sulphite may be boiled down to the sp. gr. 1.1 before it precipitates:
the liquid then contains about 12 per cent. of the salt, or 5 sulphur,
2½ oxygen, and 4½ lime. The salt precipitates from the liquid by
evaporation in the form of a white powder; it burns with a feeble blue
flame, and loses about 20 per cent.; the remainder is sulphite of lime.
When 100 grain measures of the liquid sulphuretted sulphite (1.1) are
saturated with oxymuriate of lime, they acquire 5 grains of oxygen, and
then yield 12½ grains of sulphuric acid (containing 5 sulphur and 7½
oxygen), as may be found by the barytic tests. The point of saturation
is known by the smell of oxymuriatic acid being given out permanently.
If however we oxidize the quadrisulphuret of lime by oxymuriate of
lime, the results are somewhat different. As soon as an atom of the
quadrisulphuret has received two atoms of oxygen it becomes colourless
as before, but ¾ of the sulphur is thrown down instead of ½; and
when more oxymuriate is added, so as to impart 3 atoms of oxygen to
one of the salt, a complete sulphate of lime is formed. The point of
saturation is determined by adding a small portion of muriatic acid to
the liquid, which develops the oxymuriatic acid as soon as it becomes
in excess. This method excels in the analysis of the alkaline and
earthy sulphurets in general.
When quadrisulphuret of lime is treated with an alkaline carbonate, a
reciprocal change takes place; the carbonic acid takes the lime, and
the alkali the sulphur, leaving however 1 atom of sulphur with the
carbonate which precipitates. Hence a sulphuretted carbonate of lime is
obtained and a trisulphuret of the alkali. The sulphur burns off from
the carbonate below a red heat and leaves 75 per cent. of carbonate of
lime; this affords an excellent analysis of quadrisulphuret of lime as
far as lime is the object. Thus 540 of the above 1.056 quadrisulphuret
took 100 test carbonate of potash (1.25), and gave a precipitate of
29 grains, which burned blue and left 22 grains = 12 lime, and 10
acid; but if 540 ∶ 12 ∷ 100 ∶ 2.2, as above determined synthetically:
moreover, 12 lime, 10 acid, and 7 sulphur, are as 24 lime, 20 acid,
and 14 sulphur; the composition of an atom of sulphuretted carbonate
of lime, which is analogous to the sulphuretted sulphite of lime, as
found above.
When quadrisulphuret of lime is treated with as much sulphuric acid
as is sufficient for the lime, the sulphur is in part precipitated,
but it is in union with the sulphate of lime, or at least they are
not separable by mechanical means. This compound is sold in the shops
under the name of precipitated sulphur. It is about one half sulphate
of lime, and the other half sulphur. The nitric and muriatic acids
precipitate the sulphur partially from quadrisulphuret, but the sulphur
assumes a viscid form and exhales sulphuretted hydrogen, and the
proportion of the elements of quadrisulphuret are not easily obtained
by any of these acids.
The mutual action of quadrisulphuret of lime, and the metallic salts
is curious and interesting; for instance, with nitrate of lead. Let
a solution of nitrate of lead, containing 97 oxide, be treated with
a solution of quadrisulphuret of lime by degrees, as long as a black
precipitate appears, marking the exact point of saturation; this will
be found when 36 parts of lime have entered, and 84 of sulphur; the
sulphuret of lead will fall, and when dried will weigh 145 parts,
and contain 90 lead, and 55 sulphur; that is, 1 atom of lead, and 4
of sulphur, and is consequently a quadrisulphuret of lead. The liquid
remains clear and colourless, and contains the nitric acid, lime,
oxygen of the lead, and ⅓ of the sulphur; each atom of nitric acid
combines with one of lime, which retains one of the 4 atoms of sulphur,
forming a sulphuretted nitrate of lime, consisting of 45 acid, 24 lime,
and 14 sulphur; the 7 parts of oxygen unite with 7 of sulphur to form
sulphurous acid, which require 12 parts of lime to saturate them and
7 of sulphur, forming a sulphuretted sulphite of lime: hence we see
that 28 parts of sulphur remain in the liquor, and the rest (56) unite
with the lead. If now we add gradually more nitrate of lead, a silvery
white precipitate appears, increasing till half the original quantity
is added, and then the liquid is saturated. This white precipitate is
sulphuretted sulphite of lead; when heated it soon grows black and
loses 15 or 20 per cent., being then a protosulphuret of lead. The
liquid now contains sulphuretted nitrate and simple nitrate of lime;
nitrate of lead has no effect, but nitrate of mercury precipitates a
black sulphuret.
Quadrisulphuret of lime saturated with oxygen, as has been observed,
contains sulphuretted sulphite of lime in solution, and deposits
sulphur: the liquid treated with nitrate of lead, gives as above the
white, silvery sulphuretted sulphite of lead as a precipitate, and
holds nitrate of lime in solution.
_Hydrosulphuret of lime._ This compound may be formed by passing
sulphuretted hydrogen into lime water; the water assumes a brownish
colour, but the point of saturation is not easily found, as the lime
water is not neutralized so as to shew by the colour test, and water
of itself absorbs above twice its volume of the gas. By means of a
neutral solution of nitrate of lead it may be found that 1000 lime
water in volume, require about 600 sulphuretted hydrogen, because then
a mutual saturation is observed by double affinity; that is, sulphuret
of lead and neutral nitrate of lime are formed; but otherwise the
liquid remaining is either acid or alkaline. Hydrosulphuret of lime,
as well as the other hydrosulphurets, has a peculiar bitter taste. It
forms a useful reagent in regard to metals, but is apt to be spoiled by
keeping, owing to the acquisition of oxygen.
2. _Sulphuret of magnesia._
I have not succeeded in endeavouring to combine sulphur and magnesia in
the dry way; but a liquid sulphuret is easily formed by the action of
double affinity.
Let a quantity of the liquid quadrisulphuret of lime be treated with
a solution of sulphate of magnesia, so that the sulphuric acid may be
sufficient for the lime; by digesting in a moderate heat, the sulphate
of lime is precipitated, carrying with it one fourth of the sulphur,
and a trisulphuret of magnesia remains in solution. I have not observed
any remarkable feature of distinction between this sulphuret and that
of lime, except as above noticed in the proportions of their compounds.
_Hydrosulphuret of magnesia._ This compound may be formed by pouring
sulphuretted hydrogen water into recently precipitated magnesia; it
does not differ much from that of lime. One atom of sulphuretted
hydrogen (15), combines with one of magnesia (17), and the compound is
soluble in water.
3. _Sulphuret of barytes._
_Protosulphuret._ The protosulphuret of barytes may be procured the
same way as that of lime, by heating hydrate of barytes and sulphur
till the mixture becomes red. It is very little soluble in water, and
accords in other respects with the like compound of lime. It consists
of 68 barytes and 14 sulphur, or 100 barytes and 20½ sulphur.
_Quadrisulphuret._ The quadrisulphuret of barytes may be formed the
same way as quadrisulphuret of lime, by boiling the hydrate of barytes
and sulphur together. A yellow solution of the compound is formed, not
distinguishable in appearance from that of lime; and it appears to
be analogous to it in most of its properties. By acquiring oxygen it
becomes colourless sulphuretted sulphite of barytes, and crystalizes in
needles; in this last respect it differs from that of lime. The maximum
density of liquid quadrisulphuret I have not had an opportunity of
ascertaining; it is 1.07 or upwards; that of the liquid sulphuretted
sulphite is much less than that of lime; the crystals are found in a
liquid so low as 1.004 sp. gr. They have a fine silky lustre when dry,
and a yellowish colour; heated they burn with a blue flame and leave
a white mass of sulphate preserving the same crystalline appearance
as before, and lose about 20 per cent. of weight. Ten grains of the
crystals of sulphuretted sulphite, when treated with liquid oxymuriate
of lime to saturation, require 2+ grains of oxygen and yield 8 grains
of sulphate of barytes, together with an excess of sulphuric acid which
with muriate of barytes gives 8 grains more of sulphate. From these
facts it may be concluded that the sulphuretted sulphite consists of
one atom barytes, 2 sulphur, 2 oxygen, and 2 water, and that 4 more of
oxygen are derived from the oxymuriatic acid to convert the sulphurous
oxide into sulphuric acid. The sulphuretted sulphite of barytes seems
to pass into sulphate by length of time. The weight of the atom of
quadrisulphuret of barytes is 124; the compound in mass consists of 100
barytes and 82 sulphur.
_Hydrosulphuret of barytes._ This compound may be formed in the same
manner as that of lime, and is found to have similar properties. The
proportions for mutual saturation are, I find, as in the case of lime,
15 sulphuretted hydrogen to 68 barytes by weight, or one atom of each.
4. _Sulphurets of strontites._
The protosulphuret and quadrisulphuret of strontites may be formed
in the same way as those of lime and barytes. From a few experiments
made on these compounds I have not observed any remarkable feature of
distinction between them and the corresponding ones of the other earths.
_Hydrosulphuret of strontites._ This compound may be formed in the same
way as that of lime; the proportions to produce mutual saturation will
be 1 atom of each, or 15 parts sulphuretted hydrogen, to 46 strontites
by weight.
5, 6, 7, 8, _and_ 9. _Sulphurets of alumine, silex, yttria, glucine_,
and _zircone_.
I made several unsuccessful attempts to combine alumine and sulphur.
When alumine and sulphur mixed together are heated, the sulphur
sublimes chiefly, and leaves the alumine with traces of sulphate of
alumine.
In the humid way, recently precipitated and moist alumine mixed
with sulphur and boiled in water, give a liquid with some traces of
sulphuric acid, but no sulphuret of alumine; the sulphur and alumine
both subside, and when the sulphur is either sublimed or burnt, the
alumine remains much the same as at first. When a solution of alum
is treated with sulphuret of lime, sulphate of lime is precipitated
along with the greatest part of the sulphur in a kind of feeble union
rather than mechanical mixture, it should seem; the alumine is at the
same time precipitated probably in mechanical mixture; there remain in
solution a little sulphuret of potash and sulphate of lime.
_Sulphuret of silex_ is not known, I apprehend, to exist. When
silicated potash in solution is treated with quadrisulphuret of lime, a
copious dark brown or black precipitate instantly appears; the liquid
when filtered is of a pale yellow colour, and seems to contain about
one half of the sulphur and potash, whilst the other half is thrown
down in union with the lime and silex. This black compound is probably
1 atom of lime, 2 of sulphur, 2 of potash, and 2 of silex; it cannot
therefore be accounted a sulphuret of silex.
_Sulphurets of yttria_, _glucine_, and _zircone_, are as yet, I
presume, unknown.
10. _Sulphurets of potash._
Potash has a strong affinity for sulphur and unites with it in various
ways and proportions.
1st. _In the dry way by heat._ When either pure potash or the carbonate
(salt of tartar) is heated in a covered crucible with sulphur, a
chemical union of the two principles takes place. Eight parts of dried
hydrate of potash unite to six or seven of sulphur: a heat of 4 or
500° of Fahrenheit is convenient for the purpose. If the carbonate of
potash be used, then 12 parts dried in a low red heat will require
8 of sulphur for their complete saturation: in this case a higher
degree of heat is requisite in order to expel the carbonic acid; a
low red heat seems sufficient from my trials. When the heat does not
exceed 3 or 400° a partial union takes place; the carbonate of potash,
without losing any acid, unites to ⅓ of the sulphur, and the rest of
the sulphur remains uncombined; when intermediate degrees of heat are
used, I have found the result a mixture of the pure sulphuret and the
carbonated sulphuret, with more or less of sulphate of potash. A high
degree of heat and exposure to the atmosphere produces a sulphate
instead of a sulphuret. The sulphurets obtained this way are in fusion
till poured out and cooled; they are of a _liver_ colour, and hence
were formerly called _livers_ of sulphur. They are largely soluble in
water, and give a brownish yellow solution.
2d. _In the humid way by solution._ Pure caustic potash in solution
when boiled with sulphur dissolves it largely, 42 parts of real potash
being saturated with about 56 of sulphur. If we boil a solution
of carbonate of potash with sulphur, for an hour or more, a brown
liquor is obtained, which consists of 60 parts carbonate of potash
and 14 sulphur in chemical union.--It has already been observed
that a trisulphuret of potash may be obtained by double affinity
from quadrisulphuret of lime and carbonate of potash, together with
sulphuretted carbonate of lime.
From what has been stated we may infer at least three varieties in the
compounds of sulphur and potash, viz.
1st. _Sulphuretted carbonate of potash._ This consists of 1 atom
carbonate of potash (61) with 1 atom of sulphur (14). Its analysis
may be effected as follows: the quantity of carbonic acid may be
found by the lime water necessary to saturate it; the potash may be
known from the quantity previously entering into the mixture; and
the sulphur in the same manner, or from the quantity of sulphuretted
carbonate of lead that it forms.--The sulphur may also be known, from
the quantity of oxygen it requires by means of oxymuriate of lime to
produce saturation; this I find to take place when the oxygen is half
the weight of the sulphur, or one atom to one of sulphur; it soon
happens, that one atom of sulphur deprives two others of their oxygen,
and sulphuric acid is formed whilst the other two atoms of sulphur join
the carbonate of lime and are precipitated along with it. As it may
frequently happen, that the sulphuretted carbonate is mixed with common
carbonate of potash, the proportions may be found by means of nitrate
of lead, which being cautiously dropped into the solution, lets fall
first the brown sulphuretted carbonate of lead, and then the common
white carbonate of lead.
The sulphuretted carbonate of potash absorbs oxygen and precipitates
metals much the same in appearance as the other sulphurets; but
essential distinctions are observable, some of which are noticed above,
and others will appear in the sequel.
2 and 3. The _trisulphuret_ and _quadrisulphuret_ of potash so nearly
resemble the quadrisulphuret of lime in their properties, as not to
require any additional remarks.
_Hydrosulphuret of potash._ This combination, when duly proportioned,
consists of 15 parts sulphuretted hydrogen, and 42 potash by weight,
or one atom of each. It may be formed by directly uniting the two
elements, or by decomposing hydrosulphuret of lime by carbonate of
potash. Its properties agree with those of the other hydrosulphurets.
11. _Sulphurets of soda._
I have repeated most of the experiments on the sulphurization of potash
with soda, and have not found anyone remarkable feature of distinction,
besides those which arise from the weights of the atoms.
1. _Sulphuretted carbonate of soda_ consists of 1 atom of carbonate of
soda united to 1 of sulphur; or of 47 parts of the former and 14 of the
latter.
2. _Trisulphuret of soda_ consists of 1 atom soda (28) and 3 of sulphur
(42).
3. _Quadrisulphuret of soda_ consists of 1 atom soda (28) and 4 atoms
of sulphur (56).
_Hydrosulphuret of soda._ This compound consists of one atom of each
of the elements, or 15 sulphuretted hydrogen, and 28 soda. In other
respects it agrees with hydrosulphuret of potash.
12. _Sulphuret of ammonia._
The best way which I have found of procuring sulphuret of ammonia,
is to treat quadrisulphuret of lime with the carbonate of ammonia as
long as any precipitate takes place; the precipitate is sulphuretted
carbonate of lime, 3 atoms of sulphur to 1 of carbonate of lime. The
liquid is of a pale yellow, and contains ammonia and sulphur united
in the ratio of 1 atom (of 6) to 1 of sulphur: it may therefore be
denominated the protosulphuret of ammonia.
The carbonate of ammonia is best procured by heating the common
subcarbonate of ammonia, first pulverized, in a temperature of 100°
for half an hour, or exposing it for a few days to the atmosphere.
What remains of the salt is almost without smell; it should consist of
19 parts acid, 6 ammonia, and 8 water nearly: the ammonia is usually
however a small degree in excess.
_Hydrosulphuret of ammonia._ This compound may be formed in the
dry state by combining the two gases of sulphuretted hydrogen and
ammonia over mercury; it is of a white crystalline appearance, and
very soluble in water, and forms a fuming liquor of a very pungent
smell. It may also be obtained by passing sulphuretted hydrogen into a
vessel containing liquid ammonia. I find about 110 or 120 measures of
sulphuretted hydrogen require 100 of ammoniacal gas. Hence it is 1 atom
of sulphuretted hydrogen (15), that unites to 1 of ammonia (6).
13. _Sulphurets of gold._
There exist at least two sulphurets of gold, the nature and proportions
of which are easily ascertained; though several authors assert that
no combinations of gold and sulphur are known; amongst these it is
surprizing to find Proust: indeed most of the others have probably been
led by his authority to adopt the opinion without examination. It is
not very easy to account for his deception.
Obercampf, in the Annal. de Chimie, tom. 80. 1811, is the first author
I have seen who distinctly maintains the existence of one or more
sulphurets of gold, though it seems to have been admitted previously
by Bucholz. The last author finds 82 gold unite to 18 sulphur, and the
former 80 to 20 nearly.
_Protosulphuret of gold._ This compound is formed whenever a solution
of muriate of gold is agitated with sulphuretted hydrogen gas, or with
the same united to a base, as lime or alkali. A black or deep brown
powder falls down by the addition of more gas, till the whole of the
gold is precipitated. The oxide of gold loses one atom of oxygen, and
receives one of sulphur in its place, whilst the hydrogen of the gas
is carried off along with the oxygen of the oxide. The sulphuret dried
and heated, burns with a blue flame, leaving the gold nearly pure. This
compound consists, I find, of 81 gold and 19 sulphur per cent.; or 100
gold unite to 23 sulphur.
_Trisulphuret of gold._ This compound is obtained whenever
quadrisulphuret of lime is gradually dropped into a solution of muriate
of gold; it is a black powder, not quite so deep as the former. Care
must be taken to saturate the excess of acid previously by lime water,
to prevent any uncombined sulphur precipitating. Trisulphuret of gold
being heated, burns with a blue flame, and leaves the gold nearly pure;
it loses from 10 to 45 per cent. by the process. It is constituted of
1 atom gold and 3 sulphur, or 60 gold and 42 sulphur, nearly; or 100
gold combine with 70 sulphur.
From several experiments I am led to conclude that each atom of oxide
of gold takes 3 of sulphur, and parts with 1 of oxygen to the remaining
sulphur; thus a trisulphuret of gold is formed, and an oxide of
sulphur; the liquid, being afterwards treated with oxymuriate of lime,
is found to require twice the oxygen of the gold for its saturation,
when a corresponding portion of sulphuric acid may be precipitated by
muriate of barytes.
14. _Sulphuret of platina._
Sulphur may be combined with platina in several ways, and probably
in different proportions; but the combination is not so easily
and elegantly effected as with many other metals, and hence some
uncertainty still remains on the subject.
When a salt of platina is treated with sulphuret or hydrosulphuret of
lime, or sulphuretted hydrogen water, the liquid slowly and gradually
grows dark brown and finally black; after agitation and standing a
few hours, the liquid is semitransparent, and a black flocculent
precipitate appears at the bottom. Sometimes after violent agitation,
the liquid on standing a few minutes becomes a transparent brown,
but soon grows turbid again. In the course of a few days, and by
occasional agitation, the liquid finally becomes clear and nearly free
from platina, and the precipitate may be collected on a filter and
dried. This circumstance of slow and indolent precipitation cannot be
prevented by any means I have found, such as saturating the excess of
acid, &c.
Mr. Edmund Davy, in the 40th VOL. of the Philos. Magazine, has given us
the results of his experiments and observations on the sulphurets of
platina, containing some useful and original information. He combines
platina with sulphur by heating the ammonia-muriate of platina with
sulphur; also by heating platina and sulphur in an exhausted tube;
and by sending sulphuretted hydrogen gas or water into a solution of
muriate of platina; this precipitate he calls hydrosulphuret of platina.
He has just noticed the precipitate formed by sulphuret of potash with
muriate of platina, but gives no opinion as to the compound obtained
this way. He determines three sulphurets, namely,
Subsulphuret, 100 platina + 19 sulphur
Sulphuret, 100 ---- + 28.2 ----
Supersulphuret, 100 ---- + 38.8 ----
I have obtained the sulphuret of platina in five ways: 1st. By pouring
sulphuret of lime solution by degrees into muriate of platina, and
agitating the mixture well or till it grew black each time; after
digesting for some days, repeated filtering, and drying, a black
powder is obtained: 2. Instead of sulphuret, hydrosulphuret of lime
was used; the precipitate was obtained under like circumstances: 3d.
Sulphuretted hydrogen water was used, and the precipitate obtained
in like manner: 4th. Ten grains of ammonia-muriate of platina were
treated with sulphuretted hydrogen water; by continued agitation the
yellow powder disappeared, the liquid looked uniformly black, and at
length a precipitate was formed; by repeated filtration and addition of
sulphuretted hydrogen water, the whole of the platina was thrown down,
and the liquid remained colourless; but it is difficult to discover the
exact quantity of sulphuretted hydrogen requisite for any weight of the
ammonia-muriate from the tediousness of the operation; 6 grains of well
dried black powder were obtained, besides perhaps 1 grain of loss on
the filters: 5th. Ammonia-muriate of platina was heated in a covered
crucible along with sulphur till it was judged that all the uncombined
sulphur was sublimed or dissipated.
All these sulphurets appear to me to be the same when dried in a
moderate heat. When exposed to a low red heat they yield water and
sulphurous acid, and lose about ⅖ of their weight.
The subject however, requires further investigation. The sulphurets
of platina appear of a complex nature, and the proportions of their
elements are not yet determined with precision.
15. _Sulphurets of silver._
Silver combines with sulphur in two different proportions, and forms
two sulphurets, both of them black or dark brown.
1. _Protosulphuret of silver._ This may be formed either by the dry
or humid way: if thin lamina of silver be heated with sulphur, they
combine and form this sulphuret; a higher degree of heat expels the
sulphur again. It is formed too by passing sulphuretted hydrogen or a
hydrosulphuret through a solution of silver in nitric or other acids.
The atom of silver unites with that of sulphur, whilst the hydrogen
unites with the oxygen. Of course this compound is composed of 90
silver, and 14 sulphur, and the atom weighs 104; or 100 silver unite
with 15.5 sulphur. Klaproth finds 100 silver and 17.6 sulphur; Wenzel
100 silver, and 14.7 sulphur; Berzelius 100 silver, and 14.9 sulphur;
and Vauquelin 100 silver, and 14 sulphur.
_Trisulphuret of silver._ This compound is formed whenever neutral
nitrate of silver is dropped into a solution of quadrisulphuret of lime
or alkali. Mutual saturation seems to take place when eight atoms of
nitrate meet with seven of quadrisulphuret. Trisulphuret of silver is
constituted of 90 silver, and 42 sulphur; or of 100 silver, and 46.5
sulphur. Its colour is not so dark as that of the protosulphuret. The
residuary liquid contains sulphurous acid, which is easily converted
into sulphuric by the addition of a portion of lime; and the quantity
of acid may then be determined by muriate of barytes.
16. _Sulphurets of mercury._
Mercury combines readily with sulphur both in the dry and humid way,
and that in several proportions, as under: namely,
1. _Protosulphuret of mercury._ This is most conveniently formed
by passing sulphuretted hydrogen gas through a solution of the
protonitrate of mercury, or by pouring hydrosulphuret of lime, &c.
into the same solution. The protosulphuret falls down in the state of
a black powder. It consists of 167 mercury, and 14 sulphur; or of 100
mercury, and 8.4 sulphur. The theory of its formation is the same as
that of silver.
2. _Deutosulphuret of mercury._ This is formed in the humid way
whenever sulphuretted hydrogen or a hydrosulphuret in excess is mixed
with the deutonitrate or deutomuriate of mercury (corrosive sublimate);
a brown powder is precipitated which is the deutosulphuret. If the
sulphuretted hydrogen be only one half what is sufficient to form
the deutosulphuret, then we obtain no sulphuret, but instead of it a
protonitrate or protomuriate, as was first intimated by Proust; I find
however, the atom of sulphur adheres to the atom of salt, and that it
is therefore a sulphuretted protonitrate or muriate, whilst 1 atom of
oxygen unites with the hydrogen. The brown precipitate does not change
to yellow, orange, and red, when left undisturbed for a few days, in
my experience; though this is stated to have been observed by Mr.
Accum. Notwithstanding the difference in colour, this deutosulphuret
must be the same nearly as the cinnabar and vermillion of commerce, if
Proust and others are right in their analysis of these articles. The
combination of the elements of sulphur and mercury when intended to
form cinnabar is made in the dry way by trituration, and a moderate
heat: the compound, at first black, is afterwards sublimed by a duly
regulated heat and becomes red. This compound must consist of 100
mercury and 17 sulphur nearly.
3. _Quadrisulphuret of mercury._ This compound is formed when a
solution of protonitrate of mercury is treated with quadrisulphuret of
lime, added by degrees till the clear liquid no longer gives a dark
coloured precipitate. The oxygen of the mercurial salt unites, it
should seem, to part of the sulphur, and forms sulphuric acid, whilst
the rest of the sulphur unites to the mercury. This sulphuret is a
black or dark brown powder, and when heated burns with a blue flame. It
consists of 100 mercury, and 33 or 34 sulphur, as appears to me from
the synthesis.
When the insoluble muriate of mercury (calomel), is triturated in
liquid quadrisulphuret of lime, it is soon decomposed; quadrisulphuret
of mercury is formed, with muriate of lime and sulphuric or sulphurous
acid.
When the soluble muriate (corrosive sublimate), has quadrisulphuret of
lime dropped into it by degrees; at first a yellowish white precipitate
is obtained, which increases till it is one half saturated; after
this, by continually adding more sulphuret, the precipitate grows
darker, and ends in being quite black. It is at least as high as
quadrisulphuret. Much sulphurous acid is found in the liquid.
The deutonitrate of mercury, produces a copious yellow precipitate with
quadrisulphuret of lime. Exposed to the sun, it grows black in a few
minutes on the light side, but continues yellow on the opposite side
of the jar; at the same time, an effervescence and disengagement of
oxygen gas are observed. Finally, the precipitate becomes the common
quadrisulphuret, and the liquid contains sulphurous and sulphuric acids.
The recently precipitated and washed oxides of mercury act upon
quadrisulphuret of lime. The black oxide seems to take 4 atoms of
sulphur and part with its oxygen to another portion of sulphur; but
the red oxide becomes light brown and retains the colour when dried.
It seems to take the same sulphur as the black, but whether it retains
any of the oxygen, I have not ascertained. The action is more slow
than when the nitrates are used, and more quadrisulphuret of lime is
expedient.
Mercury and sulphur combine in the dry way by trituration and by heat,
forming a black powder; but the species of compounds and quantities of
the ingredients combining in this mode, have not been ascertained.
17. _Sulphuret of palladium._
Berzelius exposed 15 grains of palladium filings mixed with as much
sulphur to a heat sufficient to expel the uncombined sulphur. The
increase of weight was 28 per cent. upon the palladium: when exposed
afresh with sulphur to heat, no addition was made to the weight.
Vauquelin heated 100 parts of the triple salt of palladium with an
equal weight of sulphur, and obtained 52 parts of a blueish white
sulphuret, very hard, and when broken exhibiting brilliant plates in
its fracture. He had previously found that 100 salt contained 40 to 42
of metal: hence 100 metal combined with from 24 to 30 of sulphur. This
agrees nearly with the above results of Berzelius. A very high degree
of heat expels the sulphur and oxidizes the metal; but a more moderate
heat leaves the palladium of a silver white colour and nearly pure.
According to this the atom of protosulphuret of palladium must consist
of 50 palladium, and 14 sulphur.
18. _Sulphuret of rhodium._
Vauquelin found that 4 parts of the ammonia-muriate of rhodium
(containing 28 or 29 per cent. of metal) being mixed with an equal
weight of sulphur, and heated, a blueish white button was obtained,
weighing 1.4. Hence 100 metal seem to take 25 of sulphur; and allowing
this to be the protosulphuret of rhodium, the atom must consist of one
rhodium 56, and one sulphur 14, making the whole weight 70.
19. _Sulphuret of iridium._
According to Vauquelin, 100 parts of the ammonia-muriate of iridium
heated with as much sulphur, yield 60 parts of black powder resembling
the other metallic sulphurets; but 100 parts of the salt were found to
yield from 42 to 45 of metal. Now supposing the last number the most
correct, it should seem that 3 parts iridium take 1 sulphur, or 100
take 33⅓. This being supposed the protosulphuret, the atom of iridium
must be 42, and that of the sulphuret 56.
20. _Sulphuret of osmium._
It is as yet unknown whether any combination of sulphur and osmium
exists.
21. _Sulphurets of copper._
Copper readily unites with sulphur both in the dry and humid way. When
3 parts of copper filings are mixed with 1 part of sulphur, and heat
applied, a brilliant combustion ensues, which indicates the union of
the two bodies. Copper leaf burns in the fumes of sulphur, as Berzelius
has observed, with great brilliancy.
The protosulphuret of copper obtained by these similar methods, when
pulverized, is black or dark coloured; it has been analyzed by various
authors, who nearly agree in their results. Proust finds 100 copper
unite with 28 sulphur; Wenzel, 100 copper and 25 sulphur; Vauquelin,
100 copper and 27 sulphur; and Berzelius 100 copper and 25 sulphur.
If the atom of copper be 56, and that of sulphur 14, the atom of
protosulphuret of copper will be 70; which gives just 100 copper and 25
sulphur.
The protosulphuret may also be formed in the humid way, by sending
sulphuretted hydrogen gas or a hydrosulphuret into a solution of
protomuriate of copper, or amongst the recently precipitated protoxide
of copper.
_Deutosulphuret of copper._ This compound is formed whenever
sulphuretted hydrogen gas or a hydrosulphuret is sent into a solution
of salt containing the deutoxide, or into the deutoxide just
precipitated from any acid. It is a dark brown powder not differing
much in appearance from the protosulphuret. It consists of 100 copper
and 50 sulphur; the weight of the atom is 84.
_Quadrisulphuret of copper._ This compound is formed by mixing
quadrisulphuret of lime with a salt of the deutoxide of copper, and
diluting the solution. A light brown precipitate falls immediately,
which is the quadrisulphuret of copper. It burns with a blue flame,
and leaves the protosulphuret. The atom consists of 56 copper and 56
sulphur, or weighs 112; and hence the sulphuret consists of equal parts
copper and sulphur.
The blue hydrate of copper recently precipitated from a salt of copper
and washed, acts upon quadrisulphuret of lime; the results, according
to my experience, is quadrisulphuret of copper, and the oxygen unites
with the sulphur remaining in the liquor.
22. _Sulphurets of iron._
Sulphur may be united to iron either by the dry or humid way, and that
in various proportions.
_Protosulphuret of iron._ This compound may be formed by passing a
hydrosulphuret into a solution of the green oxide in any acid. It
is a black powder. It may also be formed by rubbing a highly heated
bar of iron with a roll of sulphur; the two unite in a fluid form
and soon congeal into a brownish black mass. It is too a natural
production, though not very common; excellent analyses of it, as well
as of the common pyrites, were some time ago given by Mr. Hatchett.
(See Nicholson’s Journ. VOL. 10.) The protosulphuret is magnetic in a
considerable degree; it is soluble in acids, and yields sulphuretted
hydrogen. It is proper to notice that the sulphuret of iron is not
precipitated from solutions by sulphuretted hydrogen simply or without
a base. According to Mr. Hatchett this sulphuret consists of 100
iron, and 57 sulphur, which corresponds with 1 atom iron 25, and 1 of
sulphur, 14, nearly.
_Deutosulphuret of iron._ This is a natural production frequently met
with, and in various forms; it is called pyrites, or iron pyrites; it
is a yellowish mineral and often appears when broken, of a radiated
texture, but sometimes it is crystallized in cubes or dodecahedrons.
Acids have little effect upon it, except the nitric, which when
diluted attacks both the sulphur and iron; much nitrous gas is
produced, the iron is dissolved, and the sulphur chiefly converted into
sulphuric acid. This sulphuret consists, according to Proust, of 100
iron, and 90 sulphur, and with this Bucholz recently agrees (Nichols.
27--356); but Hatchett makes it 100 iron, and 112 sulphur. From an
experiment of my own on the radiated pyrites, I found nearly equal
parts of iron and sulphur. One atom of iron (25,) and two of sulphur
(28,) would give 100 to 112; but if the atom of sulphur be only 13, it
gives 100 iron to 104 sulphur. Mr. Hatchett unfortunately calculating
the proportions of the ingredients _in_ 100 sulphuret, instead of _on_
100 iron, did not notice that the sulphur in the common pyrites is just
double of that in the magnetic pyrites.
_Quinsulphuret of iron._ This combination consisting of 5 atoms of
sulphur with 1 of iron, is formed by mixing a solution of green
sulphate of iron with quadrisulphuret of lime in due proportion. I
found 50 measures sulphate 1.168 saturate 310 of 1.05 sulphuret diluted
so as to become 6 oz.; this yielded 14 grs. dried sulphuret of iron =
3.6 iron, known to be in the sulphate, and 10.4 sulphur; the liquid
contained 2+ sulphur combined with the lime and oxygen of the oxide;
for it took 2.3 oxygen by means of oxymuriate of lime to convert the
sulphur into sulphuric acid together with 1+ from the oxide, making 3+
oxygen, which unites to 2+ sulphur to constitute 5+ sulphuric acid; and
this quantity of acid was found to exist by muriate of barytes together
with five more brought in by the sulphate of iron. This sulphuret is
a yellowish brown powder; it readily exhales sulphur by heat and is
reduced to the protosulphuret; but in the open air it burns with a
blue flame and leaves the protosulphuret partially, as I apprehend,
oxidized. The theory of the formation of quinsulphuret seems to be
this: 3 atoms of quadrisulphuret of lime are requisite to saturate 2
of sulphate of iron; the 2 atoms of sulphuric acid seize 2 of lime,
three fourths of the sulphur unite to the iron, and one fourth to its
oxygen, forming 2 atoms of oxide of sulphur, which attack the 3d atom
of sulphuret and decompose it, giving its sulphur to the iron, and
neutralizing the lime (for the liquid is found neutral). In this way
10 atoms of sulphur are united to 2 of iron, and 2 of sulphur to 2 of
oxygen, with one of lime, which last compound remains in solution, and
the oxide of sulphur may be converted into sulphuric acid immediately
by the application of oxymuriate of lime.
It is remarkable that neither the green nor the yellow oxides of
iron, even when recently precipitated and not dried, seems capable of
decomposing quadrisulphuret of lime.
It is probable that trisulphuret and quadrisulphuret of iron may be
formed; but I have not ascertained the truth of this opinion.
23. _Sulphurets of nickel._
_Protosulphuret._ According to Proust, nickel unites to sulphur by
heat, so that 100 take 46 or 48; the sulphuret is of the colour of
common pyrites. (Journ. de Physique, 63 and 80). According to Mr. Ed.
Davy 100 nickel take 54 sulphur. By saturating a solution of nitrate
of nickel with hydrosulphuret of lime I obtained 40 grains from 33
protoxide or 26 metal. This was evidently the protosulphuret; it was a
fine black powder, and consists of 100 metal and 54 sulphur.
_Quinsulphuret._ This compound may be obtained from nitrate of nickel
and quadrisulphuret of lime, in the same manner as that of iron. It is
a deep black powder, and consists of 100 nickel, and 215 sulphur. By
exposure to heat, the greatest part of the sulphur burns off, and the
rest may be expelled by an increase of temperature.
Probably intermediate sulphurets may be formed; but I have not pursued
the investigation.
24. _Sulphurets of tin._
Sulphur and tin unite both in the dry and humid way, and in various
proportions.
_Protosulphuret._ This may be readily formed in the dry way as follows;
let 100 grains of tin be fused in a small iron ladle and heated to 6 or
8 hundred degrees Fahrenheit; let then small pieces of sulphur of 10
or 20 grains be successively dropped into the fused metal: a copious
blue flame will instantly arise each time, and a glowing heat will take
place, when the sulphur and tin are in contact; as soon as this ceases,
another fragment of sulphur must be dropped in, and this two or three
times repeated, heating it at last to a perfect red; the mass may then
be taken out and pounded in a mortar; a great part of it will be a
pulverulent powder, but some portions of malleable metal will still be
mixed with it, which may be separated by a sieve. This must be again
heated and treated with sulphur as before, and the whole mass will be
converted to a sulphuret. I find that 100 parts of tin become in this
way 127 grains; which is the due proportion of 52 tin and 14 sulphur,
so that no loss of tin is sustained by the process when duly managed.
According to Wenzel, 100 tin take 18 sulphur; Bergman, 25; Pelletier,
15 to 20; Proust, 20; but Dr. John Davy and Berzelius find nearly 27 as
above stated, and I have no doubt it is near the truth.
The protosulphuret of tin is a dark grey shining powder, with a streak
like molybdena or plumbago; it is not much different in colour and
appearance from native sulphuret of antimony, only less blue. It is
soluble in muriatic acid by heat, and yields sulphuretted hydrogen and
protomuriate of tin.
_Deutosulphuret._ This compound is better known than the former: it may
be formed in various ways; one is by heating a mixture of deutoxide
of tin and sulphur in a retort almost to a red heat; sulphur sublimes
and sulphurous acid is disengaged, and there remains a yellow, light
shining, flaky mass at the bottom of the retort which is the sulphuret.
It was formerly called _aurum musivum_ or mosaic gold. Pelletier and
Proust were of opinion that this product is a sulphuretted oxide of
tin; but Dr. John Davy and Berzelius have rendered it more probable
that it is a true deutosulphuret, consisting of 100 tin and 54 sulphur.
It is insoluble in muriatic or nitric acid, but slowly soluble by the
compound of the two acids; it is also soluble in potash by heat.
By exposing it to a bright red heat, it burns with a blue flame and
leaves a yellowish powder which dues not seem to differ much from
protosulphuret.
Berzelius distilled a mixture of protosulphuret and sulphur at a low
red heat, and obtained a mass of a yellow grey colour and metallic
lustre, which consisted of 100 tin, and 14 sulphur, which is just the
mean sulphur between the other two. This would seem to indicate that a
compound of the two sulphurets, 1 atom to 1, is capable of being formed.
_Hydrosulphuret of tin_ minor. This compound is formed according
to Proust, when sulphuretted hydrogen, or an alkaline or earthy
hydrosulphuret is passed into a solution of protomuriate of tin. It
is of a brown or dark coffee colour when precipitated, and black
when dried. By heat it yields water and protosulphuret. From some
experiments I am inclined to believe, that it is formed of 1 atom
protosulphuret and 1 of water: or, which is the same, 1 atom protoxide
of tin and 1 of sulphuretted hydrogen. If this be right it may be said
to be a compound of 100 tin, 27 sulphur and 15 water.
_Hydrosulphuret of tin_ major. This name is given by Proust to
the yellow compound thrown down by sulphuretted hydrogen or by
hydrosulphurets from solutions of the deutoxide of tin. When dried
moderately, the precipitate is of a dull yellow colour, and vitreous
fracture, but I find it is almost black, dried in a heat of 150° or
upwards. By moderate heat it yields water, sulphurous acid, sulphur,
and the residue is deutosulphuret of tin according to Proust. I heated
4 parts of the above previously dried so as to become a black vitreous
powder; it burned feebly with a blue flame, and after being made
moderately red, left nearly 3 parts exactly resembling the artificial
protosulphuret. I believe the dried precipitate will be found to be
constituted of 1 atom tin, 2 sulphur and 1 water; that is, 100 tin, 54
sulphur and 15 water = 169 by weight; and that it loses 27 sulphur and
15 water by a red heat, which reduces the weight just one fourth.
_Quinsulphuret of tin._ This is obtained in the humid way, by first
precipitating the oxide, and then putting quadrisulphuret of lime or
potash to the liquid containing the precipitate, till the liquid after
agitation and subsidence of the precipitate continues of a yellowish
colour. I found that 31 measures of protomuriate of tin of 1.377
= 7 grains acid, 7.5 tin and 1 oxygen, precipitated by 10 oz. lime
water, required 450 measures of 1.40 sulphuret of lime, containing 16
sulphur and 7.2 lime, for their saturation. The residuary liquid was
nearly colourless, and the precipitate dried in an oven of 100° or
more, for 10 hours, weighed 17 grains besides loss in the operation.
It was a yellow, vitreous mass, and when pulverized and heated, burned
with a blue flame, and lost 40 per cent. in weight; the residue was a
yellow grey colour, and seemed to be like the intermediate sulphuret
of Berzelius; it would not give sulphuretted hydrogen by hot muriatic
acid. Now if 52 (1 atom tin) ∶ 70 (5 atoms sulphur) ∷ 7.5 tin ∶ 10+
sulphur; hence the sulphuret should have weighed 17.5 grains, which was
the observed weight, allowing ½ grain for loss. According to this, 100
tin combine with 135 sulphur, and when burnt, the 235 are reduced to
140, the weight observed by Berzelius in the instance alluded to. The
liquid required 5 grains of oxygen from oxymuriate of lime, to convert
the sulphur into sulphuric acid, and the weight of this acid, found by
muriate of barytes, was 11 grains, indicating 4.4 sulphur. It may be
observed that the 4.4 grains, and 10 grains, do not make up the whole
(16) of the sulphuret of lime; but the reason I apprehend was, that the
quadrisulphuret was old, and did not contain the full share of sulphur,
it being usual for a small part to fall by time.
The deutomuriate of tin, precipitating the oxide in like manner,
yielded a sulphuret rather lighter yellow than the above; about 10
tin gave 25 grains of sulphuret dried in a temperature of 80 to 100°.
This compound still contained water, and I suspect it will be found
constituted of 1 atom tin, 5 sulphur, and 2 water.
25. _Sulphurets of lead._
Lead combines with sulphur in various proportions, some of which are
natural productions of great purity.
_Protosulphuret._ This is a natural production which is called galena;
it is of lead grey colour and metallic appearance, and is found both
in masses and crystallized; its sp. gr. is about 7.5. It may be
formed artificially by heating lead or its oxide with sulphur; also
by treating a solution of lead with sulphuretted hydrogen or with a
hydrosulphuret. Authors are well agreed as to the proportions of the
ingredients; 100 lead combine with from 15 to 16 sulphur. That is, 90
lead with 14 sulphur; or 1 atom of lead with 1 of sulphur.
_Deutosulphuret._ Dr. Thomson mentions a natural production or species
of galena which contains twice the quantity of sulphur of that above.
I have reason to believe that this compound is easily formed in the
humid way, by treating the precipitated oxide with the due quantity of
quadrisulphuret of lime.
_Trisulphuret_ and _quadrisulphuret_. These compounds, I find, may
be formed by means of quadrisulphuret of lime or potash. When a
solution of any salt of lead or the recently precipitated and moist
oxide, is treated with the requisite quantity of quadrisulphuret of
lime, a combination consisting of 1 atom of lead and 3 of sulphur is
formed. It is a black powder not differing much in appearance from the
protosulphuret; it is lighter and more spongy. It consists of 100 lead
and 46 or 47 sulphur. The due proportions of the elements to form the
above compound are, lead 100 parts in solution, and sulphur, 62 parts;
¼ of the sulphur is retained by the lime, and may be converted into
sulphuric acid instantly by the addition of as much oxymuriate of lime
as contains oxygen equal in weight to the sulphur, as it has already
as much oxygen as converts it into sulphurous oxide, derived from the
oxide of lead.
Quadrisulphuret of lead is to be obtained in the same way; only we must
have an excess of the sulphuret of lime, or more than 80 sulphur for
100 lead in solution, as ⅕ part of the sulphur at least is retained
by the lime. The quadrisulphuret is a black powder like the others;
it burns with a blue flame and loses nearly 40 per cent., the residue
being still black. It consists of 100 lead and 62 sulphur.
I have not ascertained whether any higher sulphuret of lead is capable
of being formed this way.
It has been already noticed (page 109), that a beautiful white, silvery
sulphuretted sulphite of lead is formed and gradually precipitated,
when nitrate of lead is dropped into a solution where as much black
quadrisulphuret of lead has been just thrown down as the sulphuret of
lime can form.
26. _Sulphurets of zinc._
Zinc and sulphur are scarcely to be united directly by heat; but by
heating the oxide of zinc and sulphur together, a combination is
effected; part of the sulphur carries off the oxygen in sulphurous
acid, and part combines with the zinc. Mineralogists give the name of
_blende_ to a mineral which is chiefly the protosulphuret of zinc: its
colour is yellowish, brown, or black almost like galena: its specific
gravity is usually 3.9 or 4.
_Protosulphuret._ The above artificial compound, or the mineral, may
be taken as examples of the union of 1 atom zinc and 1 sulphur. But
the most correct and convenient way of forming it for the purpose of
chemical investigation is, to drop a given portion of some salt of zinc
into a dilute hydrosulphuret. A white precipitate falls, which when
dried becomes a dark cream colour. It is found to consist of 2 parts
zinc and 1 of sulphur nearly; that is, of 29 parts zinc and 14 sulphur.
_Deutosulphuret_, _trisulphuret_, &c. of zinc. These combinations
may be made, up to the 5th or _quinsulphuret_, in the humid way by
quadrisulphuret of lime, &c. The oxide may be first precipitated by
lime water, or not, as we please, and then treated with quadrisulphuret
according to the degree of sulphuration required. I found 100 measures
of 1.29 nitrate of zinc with 2500 of 1.026 sulphuret of lime yield 40
grs. dry sulphuret zinc, of a yellowish white colour; the liquid was
found to retain 13 or 14 grains of sulphur, by converting it into
sulphuric acid by means of oxymuriate of lime. The nitrate contained
11½ zinc and 2.8 oxygen; so that about 28 sulphur had combined with
the zinc, and about 14 remained in solution, or ⅓ of the whole, as has
been already explained. By proportion, if 11½ ∶ 28 ∷ 29 ∶ 70; or 1 atom
of zinc (29) combines with 5 atoms of sulphur (70). The intermediate
combinations I have not particularly examined; they do not differ
much in appearance from the one just described; they burn blue and
are reduced by it to the protosulphuret; and they give sulphuretted
hydrogen by muriatic acid.
27 _and_ 28. _Sulphurets of potassium and sodium._
According to Davy and Gay Lussac, potassium and sodium unite with
sulphur by heat with vivid combustion. The compounds appear to be
protosulphurets, that of potash being nearly as 35 potassium to 14
sulphur, and that of sodium as 21 sodium to 14 sulphur. When potassium
and sodium are heated along with sulphuretted hydrogen, an union
likewise takes place; two atoms of gas unite to one of the metals,
except that 1 atom of hydrogen is liberated, corresponding of course
in quantity to that liberated by treating them with water. When the
compound thus formed is treated with muriatic or sulphuric acid,
the same quantity of sulphuretted hydrogen nearly is liberated that
was originally combined. So that the compound may be regarded as
sulphuretted hydrogen united to the protosulphurets. The colour of
these sulphurets varies from grey to yellow or reddish.
29. _Sulphurets of bismuth._
_Protosulphuret._ Bismuth combines with sulphur by heat, in the manner
already described in the account of tin sulphurets. I found 100 parts
bismuth in this way combine with 22 sulphur after 4 operations: this is
therefore the protosulphuret or 1 atom bismuth (62) with 1 of sulphur
(14). It may also be formed by substituting the oxide of bismuth for
the metal. It has a dark brown or black metallic appearance, much like
that of tin. It yields sulphuretted hydrogen in heated muriatic acid.
_Hydrosulphuret of bismuth._ When a solution of bismuth in
nitro-muriatic acid is dropped into hydrosulphuret of lime, a black
powder precipitates, which, when dried in the common temperature,
appears to be hydrosulphuret of bismuth, or one atom sulphuretted
hydrogen and one oxide of bismuth. It yields sulphuretted hydrogen by
cold muriatic acid. But if the precipitate be dried in a heat of about
200°, the atom of water seems to be expelled, and there remains only
the protosulphuret. Thus I found 69 parts oxide of bismuth unite to 15
sulphuretted hydrogen to form 84 hydrosulphuret of bismuth, when dried
in the air; but upon being heated a little, it lost 8 parts of water
and was reduced to the protosulphuret, retaining in great part the same
appearance as before.
_Deutosulphuret and trisulphuret of bismuth with oxygen._ When
nitro-muriate of bismuth is thrown into water the oxide is
precipitated; if the acid water be decanted, quadrisulphuret of lime be
put to the moist oxide and due agitation be used, the oxide abstracts
sulphur from the lime so as to obtain 2 or 3 atoms for each one, if
the sulphur be sufficient in quantity. To 6 oz. water I put 100 grain
measures of 1.286 nitro-muriate, which I knew from its formation
contained 20 oxide; after the precipitate had subsided I poured off 5
oz. of acid water, and to the remaining precipitate diluted with water
I put 300 of 1.056 sulphuret of lime and agitated for 10 minutes.
There were obtained 33 grains of brownish black sulphuret of bismuth
dried for some hours in a temperature of 120°. I put the above 33
grains into a gas bottle with 100 muriatic acid and boiled it; there
were obtained only 2 or 3 cubic inches of sulphuretted hydrogen, the
oxide was dissolved and sulphur liberated; the sulphur collected and
dried weighed 9 grains, and the oxide precipitated again from the
muriatic acid by water and dried, weighed 17 grains, besides loss.
From this it is evident the oxygen of the oxide must have been chiefly
retained in the compound, and must have united to 2, and in great part
to 3, atoms of sulphur. For 20 oxide would require 12 sulphur to form
trisulphuretted oxide; and there was evidence of its having nearly, if
not wholly, that quantity.
30. _Sulphurets of antimony._
_Protosulphuret._ This is a natural production, and found in the state
of a dark grey mineral of metallic appearance, and of the sp. gr. 4.2.
It may also be formed artificially by uniting metallic antimony and
sulphur by heat. Most authors nearly concur in assigning to it 74 parts
antimony and 26 sulphur, per cent. That is, 1 atom antimony (40) and 1
of sulphur (14). It yields sulphuretted hydrogen by muriatic acid and
heat, and a solution of the metallic oxide is obtained.
_Hydrosulphuret._ When antimony is precipitated from a solution, by
sulphuretted hydrogen or a hydrosulphuret, or from an alkaline solution
of the sulphuret by an acid, it appears in the form of an orange yellow
powder, denominated golden sulphuret. It is constituted of 1 atom
sulphuretted hydrogen and 1 of protoxide of antimony; it readily yields
sulphuretted hydrogen by muriatic acid, and the oxide combines with
this acid. Exposed to heat, water is expelled and protosulphuret left.
It is constituted of 40 antimony, 7 oxygen, 14 sulphur and 1 hydrogen;
or of 54 protosulphuret and 8 water.
_Bisulphuretted_, _trisulphuretted_ and _quadrisulphuretted oxide of
antimony_. When crystallized muriate of antimony is agitated along with
dilute quadrisulphuret of lime, an orange yellow compound is formed,
consisting of the oxide and sulphur. To 350 quadrisulphuret of lime,
diluted with lime water, I put 22 grains moist crystals of muriate, and
agitated well for some time. Got 26 grains dry yellow sulphuret, which
heated burned blue, and left from 13 to 14 black grey sulphuret, equal
to 10 antimony nearly; hence it must have been a quadrisulphuret, or
rather sulphuretted oxide; for, by heating this compound in muriatic
acid, a solution is obtained and sulphur liberated without the
extrication of gas. Less of the sulphuret of lime would have produced a
sulphuret of the same colour, but containing less of sulphur; so that
it is evident various proportions may exist in combination. Instead of
the crystallized muriate, the recently precipitated oxide, nearly free
from acid, may be used to produce these compounds.
31. _Sulphuret of tellurium._
Tellurium unites with nearly its weight of sulphur, by heat, according
to Davy. It is probable that as usual in such cases, a protosulphuret
is formed. This would lead to the conclusion that the atom of tellurium
is only equal in weight to that of sulphur; which does not accord with
results from the other combinations of tellurium, and hence the above
fact may not perhaps be sufficiently ascertained.
32. _Sulphurets of arsenic._
Arsenic may be combined with sulphur by exposing a mixture of the
metal and sulphur or of the white oxide and sulphur, to a heat
approaching to redness. In the latter case more sulphur is required,
because the oxygen is carried off in the shape of sulphurous acid.
Three parts of arsenic with two, three or more of sulphur may be used;
the heat should be less if a greater proportion of sulphur is intended
to be united. As both the elements are volatile in a moderate heat, and
that in unequal degrees, considerable difficulty occurs in ascertaining
by the synthetic mode, the proportions of the elements combined; if
too little heat be used, only a mechanical mixture is obtained, of any
proportions we please; if too much heat be used, part of the arsenic as
well as part of the sulphur sublimes, and the sulphuret itself sublimes
at a heat not much exceeding that required for their union. Hence in a
great measure we have the discordant results of those who have taken
the synthetic method. The analytic method is to be preferred, and those
who have taken it have succeeded the best; but even this is attended
with greater difficulties than with most of the other sulphurets.
The artificial sulphurets of arsenic constitute two varieties chiefly,
and these are also found native in various parts of the earth.
_Protosulphuret._ Native sulphuret of arsenic, called orpiment, is
found in Turkey and elsewhere in considerable masses; when broken it
exhibits a foliated structure, somewhat flexible, and of a brilliant
golden yellow colour. Its specific gravity is usually about 3.2; at
least that was the case with the specimen I used. When heated so as
to be near melting, its surface reddens, probably by the loss of
sulphur. The same sulphuret is procured artificially in the humid way
whenever a solution of the oxide of arsenic in water, &c. is treated
with sulphuretted hydrogen, or a hydrosulphuret, and afterwards with
an acid; or when this or any other species of sulphuret of arsenic is
dissolved in an alkali and the solution treated with an acid. Kirwan
in 1796 states, that it is generally thought to consist of 100 arsenic
and 11 sulphur, but that Westrumb says it contains 100 arsenic and
400 sulphur, which Kirwan thinks more probable; they are both however
very wide of the truth. Thenard, in the 59 VOL. of the An. de Chimie,
1806, asserts that it consists of 100 arsenic and 75 sulphur; but he
does not point out the experiments on which this result rests; and it
is not very near the truth. Laugier in the same An. VOL. 85, for 1813,
in a paper of great merit, finds the native orpiment to contain 38
per cent. of sulphur; his method is to dissolve the orpiment in warm
dilute nitric acid; to precipitate the sulphuric acid by nitrate of
barytes, and from the sulphate of barytes infer the sulphur; the rest
he considers as arsenic, not knowing how to detach the arsenic acid
from the nitric acid so as to determine the arsenic by experiment. I
have pursued this method with the advantage of being able to determine
the arsenic as well as the sulphur: Ten grains of orpiment in fine
powder were dissolved in 100 measures of 1.346 nitric acid diluted with
as much water, by digesting in a heat so as to keep a constant moderate
effervescence for about 2 hours. The liquid obtained, being diluted,
yielded 536 measures of 1.061. By carefully and gradually dropping
in muriate of barytes I found 150 measures of 1.162 just sufficient
to saturate the sulphuric acid, and the sulphate of barytes produced
dry was 28 grains, the loss I estimated 1 grain: now one third part
being sulphuric acid, and ⅖ of the acid being sulphur, we have ²/₁₅ of
29 = 3.87, or 3.9 for sulphur. The residuary liquid was then treated
with lime water till an excess was manifest, and produced no farther
precipitate; the arseniate of lime was collected and dried, and gave 16
grains. Now I had determined by experiments hereafter to be related,
that ⁴/₇ of arseniate of lime are acid and ⅔ of the acid are arsenic;
hence ⁸/₂₁ of 16 = 6.1 for the arsenic, which added to 3.9 sulphur,
make up the 10 grains of orpiment.
When this orpiment is treated with caustic alkali, it is completely
dissolved; it is thrown down by acids I find unaltered. If 61 arsenic
combine with 39 sulphur, 100 must take 64 nearly; which corresponds
with 1 atom of each, or 21 arsenic + 13 or 14 sulphur.
_Subprotosulphuret._ Sulphur and arsenic are found native in certain
places, combined in masses of a brownish red or orange colour and
glassy fracture: this combination is called _realgar_, and is also
manufactured in large quantities in Saxony, chiefly for the use
of calico-printers. Its constitution and specific gravity vary
considerably, owing chiefly I imagine to the greater or less heat
to which it is exposed, and to the proportions of the elements in
the first mixture. I have specimens of 3.3 and 3.7 sp. gr.; and it
is probable these are not the extremes; the heaviest is the darkest
colour. Of course the heaviest contains the most arsenic, and I
have reason to believe that the sp. gr. is nearly as good a test
of the proportions of the elements as chemical analysis. Realga
when pulverized is of an orange colour: it is much sooner dissolved
in dilute nitric acid and requires less, than the same weight of
orpiment. Caustic alkali dissolves it partially, taking up the
protosulphuret and leaving the excess of arsenic, the quantity of which
may hence be ascertained. Ten grains of realgar took 80 measures of
1.347 nitric acid, diluted with as much water; digested in a heat of
about 150° it was all dissolved in 1½ hour, and yielded 536 liquid of
1.05 sp. gravity. This treated as before gave 24 sulphate of barytes =
3.2 sulphur, and 18 arseniate of lime = 6.9 arsenic. This result agrees
nearly with Laugier’s in regard to the sulphur in native realgar: but
the artificial realgar, which he made by combining arsenic and sulphur,
yielded him 40 per cent. sulphur by my estimation and 42 by his own:
the sp. gravity of his artificial realgar is not given. Westrumb
estimates realgar at 100 arsenic and 25 sulphur, and Thenard at 100
arsenic and 33 sulphur. But from the above it must be concluded to
contain 100 arsenic and 45 to 50 of sulphur. One hundred parts of the
same realgar heated in caustic potash were resolved into 78 orpiment
taken up by the liquid and 22 arsenic precipitated.
It appears to me most probable that a true subsulphuret would be most
convenient for the printers’ use, or one containing 100 arsenic and 32
sulphur, that is, 2 atoms arsenic and 1 sulphur. The object being to
deoxidize indigo and obtain it in solution in a green state, we may
suppose that 1 atom arsenic takes the oxygen from the indigo and then
forms arseniate of lime which precipitates, whilst the other atom in
union with the sulphur, takes the green indigo and unites it to the
potash, making a quadruple compound of arsenic, sulphur, green indigo
and potash in solution. If this view be right the heaviest and darkest
coloured realgar of commerce must be the most advantageous for this
purpose. Some printers however prefer the protosulphuret.
_Deutosulphuret._ Proust, by heating 100 arsenic with 300 sulphur in
one instance got 222 parts, and in another 234 parts of a transparent
deep greenish yellow sulphuret, (Jour. de Phys. 59--p. 406. 1804). Now
it is very remarkable that if we take the atom of sulphur at 13 and
that of arsenic 21, one of this and two of the former will be found as
100 to 124, together 224; but if sulphur be 14, then the proportion
will be 100 to 133, together 233. It seems more than probable that
Proust had accidentally used that degree of heat in the combination
which is requisite for forming the deutosulphuret. It is probable too
that Laugier always used a higher heat, as he uniformly obtained the
same (lower) sulphuret whatever were the proportions, the excess of
either being sublimed or separated by the heat.
_Trisulphuret_, _quadrisulphuret_, &c. When a solution of the oxide of
arsenic is treated with quadrisulphuret of lime, little precipitate
appears; but if muriatic acid be dropped in, a fine yellow precipitate
is formed. This I have reason to think is sometimes a trisulphuret,
and at other times a quadrisulphuret or higher; but it is difficult
to investigate these compounds, and on that account I speak with some
uncertainty.
33. _Sulphuret of cobalt._
Sulphuretted hydrogen does not precipitate cobalt from solutions
containing that metal; but hydrosulphurets precipitate it.
_Protosulphuret._ This compound is obtained whenever a neutral solution
of cobalt is treated with hydrosulphuret of lime, &c. or it may be
obtained from any acid solution by first precipitating the blue oxide
by an alkali, and then introducing sulphuretted hydrogen into the
mixture. By this last method I found a solution previously known
to contain 44 parts by weight of protoxide to absorb 15 parts of
sulphuretted hydrogen; when filtered and dried in a heat of 100° it
yielded 51 parts of protosulphuret. In appearance it resembles many of
the other black sulphurets. It consists of 100 cobalt and 38 sulphur;
Proust finds 40 sulphur, but he considers it only an approximation.
The same sulphuret may be formed by heating the oxides of cobalt and
sulphur together to a red heat; at least a combination is effected as
Proust observed, but I have not investigated the proportions. Sulphur
does not seem to combine with the metal in this way.
_Deutosulphuret_ ... _dodecasulphuret_. When the recently precipitated
and moist oxide of cobalt, the neutral muriate, or acid muriate of
cobalt, as well as other salts of the same, are treated with dilute
quadrisulphuret of lime, sulphurets of cobalt are formed in various
proportions according to the ingredients, from the deutosulphuret to
the dodecasulphuret: these precipitates are all black and not easily
distinguished in appearance; but there is reason to believe they are
true chemical compounds.
34. _Sulphurets of manganese._
Though sulphur and manganese do not unite directly, they can be brought
into union by intermediate bodies, both in the dry and humid way.
_Protosulphuret._ This compound may be formed by heating to a low
red, a mixture of the oxide of manganese and sulphur, or of the white
carbonate of manganese and sulphur; or it may be formed by treating a
solution of manganese by a hydrosulphuret, (sulphuretted hydrogen not
producing any precipitate); this last method seems to produce a dry
hydrosulphuret of manganese, which being heated to red nearly, parts
with water and a little sulphur and there remains the protosulphuret.
The protosulphuret is of a snuff brown colour; but the hydrosulphuret,
when recently precipitated is of a light drab colour, which grows
deeper when exposed to the air, and when dried becomes brown like
the protosulphuret; when heated, the colour is not much changed.
The hydrosulphuret of manganese gives sulphuretted hydrogen by cold
muriatic acid, and the protosulphuret gives the same by the acid
heated.
The proportion of the elements in the protosulphuret may be inferred
from the fact that the black oxide yields its own weight of
protosulphuret; that is, 156 grains, composed of 100 metal and 56
oxygen give 156 of sulphuret; hence the atom of metal, 25, unites with
one of sulphur, 14. I found 32 of the protoxide in solution unite to 15
of sulphuretted hydrogen to form 47 hydrosulphuret dried in 100°. This
lost about 8 parts or rather upwards by heat.
_Deutosulphuret_, _trisulphuret_ and _quadrisulphuret_. These may be
formed by treating neutral solutions of manganese, or the recently
precipitated oxide, by quadrisulphuret of lime. They are formed
somewhat slowly and by considerable agitation with a smaller or greater
proportion of the lime sulphuret. They are all light drab, and are
reduced to the protosulphuret by heat.
35. _Sulphuret of chromium._
I have not had an opportunity of ascertaining whether chromium or its
oxides combine with sulphur or not, though several attempts were made
for that purpose.
36. _Sulphuret of uranium_.
From the experiments of Bucholz it would seem that uranium may be
combined with sulphur, but the proportions have not been ascertained.
(An. de Chimie. 56--142.)
37. _Sulphuret of molybdenum._
From Bucholz and Klaproth’s analyses of molybdena it would seem that
the native sulphuret consists of 60 metal and 40 sulphur; but it does
not appear whether this should be considered as the protosulphuret or
the deutosulphuret. If it is the protosulphuret the atom of molybdenum
weighs 21, but if the deutosulphuret, the atom of metal weighs 42; and
the atom of the sulphuret or molybdena must weigh either 35 or 70.
38. _Sulphuret of tungsten._
According to Berzelius, a sulphuret of tungsten may be obtained, by
heating a mixture of tungstic acid and sulphuret of mercury in the
proportion of 1 to 4, in a crucible. The mixture in his experiment was
covered with charcoal and the crucible inclosed in another containing
charcoal; the whole was then exposed to the heat of a furnace for half
an hour. The sulphuret obtained was a greyish black powder; it was
found to consist of 100 metal and 33¼ sulphur, or about 3 metal to 1
sulphur. Hence this must be the deutosulphuret if we consider the atom
of tungsten to be 84; but considering the high degree of heat to which
it was exposed, it would seem more likely to be the protosulphuret; if
so, the atom of tungsten must be considered as 42 only, or half of the
other number.
39. _Sulphuret of titanium._
No compound of titanium and sulphur has been formed.
40. _Sulphuret of columbium._
This combination is unknown.
41. _Sulphuret of cerium._
This combination is also unknown.