EARTHY, ALKALINE, METALLIC AND OTHER PHOSPHURETS.
Phosphorus like sulphur is capable of being combined with several of
the earths and metals as well as with other bodies; but the combination
is not so easily effected, and the products are less interesting
than those of sulphur: from considerations of these circumstances
together with those of the expence and danger in making experiments
on phosphorus we may account for, this class of bodies being as yet
imperfectly known.
Margraf in 1740 attempted to combine phosphorus with many of the
metals; but his experiments were mostly unsuccessful.
Gengembre in 1783 endeavoured to unite phosphorus with the alkalies; in
this he failed of success, but discovered the phosphuret of hydrogen,
or the spontaneously inflammable gas now denominated phosphuretted
hydrogen. (Journal de Physique, 1785.)
In 1786 Mr. Kirwan published some experiments on phosphuretted
hydrogen, (Philos. Trans.); he ascertained that water impregnated with
this gas had the property of precipitating various metals from their
solutions.
The ingenious and indefatigable Pelletier has more merit than any other
person in his investigations of the phosphurets. An important memoir
of his on the manufacture of phosphorus in the large, is given in
the Journal de Physique for 1785; in this he states that 4 or 5 lbs.
sulphuric acid are commonly requisite for 6 lbs. calcined bones; and
that from 18 lbs. calcined bones he obtained by the usual process, 12
oz. of phosphorus. In 1788 he read an essay on the phosphurets of gold,
platina, silver, copper, iron, lead and tin. (An. de Chimie, 1--106).
In 1790 he published an essay on the combinations of phosphorus with
sulphur. (_Ibid._ 4--1). An additional memoir was published in 1792
on the same metallic phosphurets; and another on the phosphurets of
mercury, zinc, bismuth, antimony, cobalt, nickel, manganese, arsenic
and the other metals.
M. Raymond in the An. de Chimie, 1791, recommends, instead of potash,
moist hydrate of lime and phosphorus in order to obtain phosphuretted
hydrogen with greater facility; and in the same Annals for 1800 he
asserts that water absorbs a considerable portion of phosphuretted
hydrogen, and becomes capable of precipitating metals from their
solutions in acids, and of forming phosphurets, in this respect
resembling sulphuretted hydrogen.
Mr. Tennant discovered in 1791 that carbonic acid combined with the
earths and alkalies is capable of decomposition by phosphorus, in a
red heat; and Dr. Pearson, following up the discovery, found that pure
or caustic lime may be united to phosphorus by heat so as to form
phosphuret of lime; and that this dry compound when put into water is
decomposed and gives out bubbles of phosphuretted hydrogen gas, which
as usual explode spontaneously on reaching the surface of the water and
coming into contact with the air.
In 1810 I published the method of analysing phosphuretted hydrogen by
Volta’s eudiometer; having found that this gas and oxygen may be mixed
together in a narrow tube without explosion and afterwards exploded as
other similar mixtures by an electric spark.
Dr. Thomson published an essay on phosphuretted hydrogen in the Annals
of Philosophy for August, 1816. He agrees with me very nearly as to the
constitution and properties of this gas, as far as I have gone; but he
has ascertained several additional properties of the gas, which I shall
advert to in the sequel.
Sir H. Davy and Gay Lussac have investigated several compounds of
phosphorus, particularly with muriatic and oxymuriatic acids, and with
the new metals potassium and sodium, which I shall have to notice in
their proper places.
Other authors have written on phosphurets besides those I have
mentioned, but they do not require to be particularly distinguished
in this enumeration. We shall therefore proceed to describe the
phosphurets more particularly.
1. _Phosphuret of hydrogen._
From recent experiments which I have made on phosphuretted hydrogen
gas, I find the account already given (VOL. 1. page 456) is deficient,
and in several respects inaccurate; I shall therefore substitute the
following, as more perfect and correct.
Phosphuretted hydrogen may be obtained nearly pure, by the methods
recommended by Dr. Thomson. Phosphuret of lime that has been carefully
secluded from the atmosphere, may be put into a small phial filled
with water, acidulated by muriatic acid; into this a cork with a bent
tube must be immediately put under water, so that the phial and tube
are both full of water; gas soon begins to appear, which rising to
the top of the phial, expels a corresponding portion of water, and in
due time the gas itself comes over and may be received as usual: if
the phial in which the gas is generated be warmed to 140 or 150°, the
gas is given out more readily. A half ounce phial with 20 grains of
phosphuret in small lumps, will produce 3 or 4 cubic inches of gas.
If the phosphuret of lime has been previously exposed for a few hours
to the atmosphere, the gas is more abundant, but consists chiefly of
hydrogen, mixed with a little phosphuretted hydrogen.
Pure phosphuretted hydrogen is distinguished by the following
properties: 1. It explodes when coming into the atmosphere in bubbles,
and a white ring of smoke subsequently ascends: 2. It is unfit for
respiration, and for supporting combustion: 3. Its specific gravity
is 1.1 nearly, that of atmospheric air being unity: 4. Water absorbs
fully ⅛ of its bulk of this gas, which is expelled again by ebullition
or by agitation with other gases, but not without some loss: 5. A
small portion being electrified for some time, deposits abundance of
phosphorus, and expands from one volume to 1⅓ nearly, which is found to
be pure hydrogen: 6. Liquid oxymuriate of lime absorbs phosphuretted
hydrogen, converting it into phosphoric acid and water, and leaves any
free hydrogen that may be present; hence we are enabled to ascertain
the proportion of free hydrogen in any such mixture, an important
point as far as regards this gas: 7. One volume of pure phosphuretted
hydrogen, requires two volumes of oxygen for its complete combustion by
an electric spark, in Volta’s eudiometer; (the gases must be previously
mixed in a tube not more than ³/₁₀ of an inch in diameter, to prevent
an explosion in the act of mixing, after which they may safely be
transferred into any other vessel); the result of the combustion is
phosphoric acid and water: 8. One volume of phosphuretted hydrogen,
mixed with from 2 to 6 volumes of nitrous gas, may be exploded by
electricity in Volta’s eudiometer; or it may be exploded by sending
up a bubble of oxygen, without electricity; in like manner, may the
mixtures of phosphuretted hydrogen and oxygen be exploded by a bubble
of nitrous gas: 9. One volume of phosphuretted hydrogen, mixed with
4, less or more, of nitrous oxide, is also explosive by electricity,
but the mixture undergoes no change without electricity, at least in
a day: 10. Mixtures of phosphuretted hydrogen and nitrous gas have a
slow chemical action, by which in from 1 to 12 hours, the phosphuretted
hydrogen is burnt and the nitrous gas decomposed into nitrous oxide and
azotic gas: 11. According to Sir H. Davy and Dr. Thomson, phosphuretted
hydrogen gas being heated along with sulphur in a dry tube, the gas is
decomposed and a new gas, sulphuretted hydrogen, is formed, and the
phosphorus unites with the sulphur. Davy says the gas is doubled in
volume by this operation; but Thomson says it remains the same; some
doubt therefore exists respecting this fact: 12. When phosphuretted
hydrogen gas is let up to oxymuriatic acid gas, a quick combustion with
a yellow flame is observed, and the result varies according to the
proportions: when one volume phosphuretted hydrogen is put to 3 or 4
of acid gas, both of the gases disappear, and muriatic and phosphoric
acids are produced.
As these properties differ in many respects from those hitherto
assigned to this gas, it will be necessary to enlarge upon them. The
sp. gr. of this gas has already been adverted to, (VOL. 1.), and its
great variation from .3 to .85; more recently Dr. Thomson finds it
about .9. In all these instances it was, I have no doubt, contaminated
with less or more of hydrogen; at least it was so in my own instance;
for, I have the proportion of oxygen which it required for its complete
combustion, both before and after it was weighed. It was what I then
thought pure gas: that is, 100 volumes required nearly 150 of oxygen;
but I am now convinced that gas of this description contains ⅓ of its
volume of free hydrogen; hence the correction of the sp. gravity. Davy
estimates the sp. gr. of the gas which he denominates _hydrophosphoric_
at .87 or 12 times that of hydrogen; this gas, as will appear from this
and other properties, is in all probability phosphuretted hydrogen gas,
nearly pure.
The absorption of this gas by water, has been stated variously. In 1799
M. Raymond found that water absorbs rather less than ¼ of its volume of
this gas: in 1802, Dr. Henry rates its absorption at ¹/₄₇ only; in 1810
I found it ¹/₂₇; in 1812, Davy found it (hydrophosphoric gas) to be ⅛;
in 1816, Dr. Thomson found it to be ¹/₄₇; I now estimate it as stated
above at ⅛. These enormous differences may be partly accounted for by
varieties in the gas; and partly from the theory of the absorption
not being understood; but these are scarcely sufficient excuses in
all the cases. I find that my early experiments on the absorption of
phosphuretted hydrogen by water, were made prior to the discovery of
the method of analysing the gas by electric combustion; consequently
they were deficient in regard to the quality of the gas, both before
and after agitation; the best gas that ever I had, was such as took
150 oxygen per cent. for its combustion, exclusive of any common air;
and it was often such as to require considerably less. The bottle
which I used for the purpose in 1810 contains 2700 grains of water; at
first I charged water with hydrogen: into this 120 grain measures of
phosphuretted hydrogen were put, and the whole well agitated: there
were left 98 measures;--this proved that the gas was more absorbable
than hydrogen: into the same water were put 98 more phosphuretted
hydrogen and agitated; out, 80; this confirmed the proof: Into the same
water were put 97 hydrogen and agitated well; out 105: This shewed
that the hydrogen had expelled a part of the gas again, and was less
absorbable of the two. As the phenomena were much the same as if oxygen
had been used instead of phosphuretted hydrogen, it was concluded to
have the same absorbability.
In the present instance, however, I have been more circumstantial;
after repeatedly agitating water with pure azotic gas, so as to
saturate it and expel the oxygen, I then put in 110 grain measures
of phosphuretted hydrogen composed of 100 pure gas, 5 hydrogen, and
5 azotic gas or rather atmospheric air. After due agitation, all was
absorbed but 35; this was mixed with a known portion of oxygen and
exploded; the diminution was 19 measures; the oxygen remaining was
determined by hydrogen; from which it appeared that 10 combustible
gas had taken 9 oxygen. Now 10 being ²/₇ of 35, we may consider the
water as ²/₇ impregnated with the phosphuretted hydrogen, and ⁵/₇ with
azote; but as there were 105 combustible gas and only 10 left, 95 must
have entered the water and caused it to be ²/⁷ charged with the gas;
whence we may infer that 332 gas would have been a full charge for 2700
water, which is almost exactly ⅛, as stated above. Other experiments
gave corresponding results. On admitting 51 azotic gas to the water,
and agitating it a good deal for 4 or 5 minutes, there came out 51
measures or the same volume: this was found in the same way to consist
of 43 azote and 8 combustible, which took 10 oxygen. Again 51 azote
was agitated in the water, and there came out 51, of which 5 + were
combustible and took 9 oxygen. After this the bottle of water was put
into a pan of water which was raised to the boiling heat, a bent tube
filled with water being adapted to the water bottle, and having its end
immersed in water: by this operation gas was expelled from the water,
and caught in the neck of the bottle; when it amounted to 22 grain
measures it was transferred and was found to consist of 17 azote + 5 +
combustible, which took 10 oxygen. By these experiments we see that the
gas is expelled again from the water, both by ebullition and by other
gases, nearly the same in quality, but much diminished in quantity,
the reason of which is not very obvious. The liquid now required 30
measures of oxymuriate of lime, equivalent to 100 measures of oxygen,
before it was saturated; that is, there appeared to be 50 phosphuretted
hydrogen remaining in the water. Adding a little lime water threw down
a very sensible quantity of phosphate of lime.
The expansion of phosphuretted hydrogen by electricity is a subject on
which there has been as much diversity as on its absorption. In 1797,
Dr. Henry found that it expanded “equally with carbonated hydrogen.”
(Philos. Trans.). In 1800, Davy states that phosphuretted hydrogen was
not altered in volume by electricity. (Researches, page 303.) In 1810,
my experiments led me to adopt the same conclusion. In 1811, Gay Lussac
found (Recherches, page 214), that potassium heated in phosphuretted
hydrogen gas, expanded 100 volumes to 146; he infers that the true
expansion ought to have been to 150. In 1812, Davy observes, that when
electric sparks are passed through gases of this kind, “usually there
is no change of volume.” (Elements of Chem. Philos. p. 294.) But he
adds that when a gas (sp. gr. 6, hyd. being 1) was heated with zinc
filings over mercury, there was an expansion of volume of more than ⅓.
Also potassium heated in it, made 2 parts become 3 or 3, parts rather
more than 4, (1810); the residual gas in these cases was pure hydrogen.
Hydrophosphoric gas (sp. gr. 12) yielded 2 volumes of hydrogen, by
heating potassium in it. In 1816, Dr. Thomson found that by electric
sparks phosphorus was deposited, and hydrogen remained “exactly equal
to the original bulk of the phosphuretted hydrogen.” Lastly, in 1817,
I found by two experiments, that by electrifying 30 grain measures
of phosphuretted hydrogen in a tube over water, uninterruptedly for
nearly 2 hours, I produced an expansion of ⅕, or the gas became 36
measures; originally the gas contained 2½ common air, and the rest was
combustible so that 100 measures took 190 oxygen. By exploding the
residue with oxygen, I found that ¹/₁₅ or ¹/₂₀ of the phosphuretted
hydrogen still remained undecomposed. Taking these observations into
consideration along with the fact, that 1 volume of the purest gas
requires 2 of oxygen for its combustion, I conclude that the true
expansion should be ⅓, or 3 volumes of gas should become 4, and then it
will be found that ⅓ of the oxygen is joined to the hydrogen and ⅔ to
the phosphorus, which accords with what appears to me the only correct
view of the constitution of phosphoric acid, namely, 2 atoms of oxygen
to 1 of phosphorus.
The action of oxymuriatic acid, whether free or combined, on
phosphuretted hydrogen, is curious and interesting; in both cases it
effects a complete and instantaneous combustion of both phosphorus
and hydrogen; when the acid is put to in the state of gas, it not
only burns the phosphuretted hydrogen, but any free hydrogen that may
be present; but this has a limit: if the phosphuretted hydrogen be
largely diluted (90 per cent.) with hydrogen, this last is wholly left;
the reason seems to be, the phosphuretted hydrogen burns at a lower
temperature; and hence probably it is, that liquid oxymuriate of lime
burns the phosphuretted hydrogen, but not the hydrogen gas.
The quantity of oxygen necessary to saturate a given volume of
phosphuretted hydrogen is easily found. Oxygen gas containing a known
per centage of azotic gas, must be used in some excess, mixed with a
due portion of the gas. After exploding the mixture, the loss must be
observed, and then the remaining oxygen must be found by exploding
it with hydrogen. Hence the true volume of oxygen spent by the first
explosion, and that of the combustible gas are both determined. The
due proportion of oxygen is so nearly 2 to 1, that I have not been
able to determine on which side the truth lies. Dr. Thomson says that
when phosphuretted hydrogen and oxygen are mixed, two volumes to one,
a white smoke takes place, the volume of oxygen gradually disappears,
and there remains behind a quantity of hydrogen exactly equal to the
original volume of the phosphuretted hydrogen. I have observed nothing
at all like this. A mixture of phosphuretted hydrogen and oxygen stood
24 hours without sensible diminution, and afterwards being exploded, 2
volumes of oxygen disappeared for 1 of phosphuretted hydrogen, the same
as would have done at the moment of mixing. Perhaps the _temperature_
may have some influence; mine was about 55°.
I have tried the minimum of oxygen that will consume or dissipate
phosphuretted hydrogen gas. It may be exploded with about ¼ of its
volume of oxygen, with the same phenomena as Davy observed of the
hydrophosphoric gas. Phosphorus is thrown down and a volume of
combustible gas is left about 10 per cent. greater than the original
volume of phosphuretted hydrogen. This gas is nearly pure hydrogen.
Hence the whole gas may be dissipated at 2 successive explosions, by
rather less than an equal volume of oxygen. If phosphuretted hydrogen
be exploded with an equal volume of oxygen, phosphorous acid, water and
a little phosphoric acid are formed, and some hydrogen remains.
One of the most remarkable properties of phosphuretted hydrogen, is
that announced by Dr. Thomson, namely, its combustion with nitrous
gas by electricity; and the _slow_ combustion by the same gas, which
I have mentioned above is a fact still more difficult to explain. I
tried the combustion of phosphuretted hydrogen by nitrous gas and
electricity in 1810, but did not succeed. The reason was, the gas was
not sufficiently pure. No phosphuretted hydrogen that is not 70 or
80 per cent. pure, can, I imagine, be exploded by nitrous gas; even
the purest requires sometimes more than one spark, when mixed in the
most favourable proportions; and I have known instances in which the
mixture has exploded after electrification for a few minutes. An excess
or defect of nitrous gas, occasions oxygen or hydrogen to be found in
the residual gas, just as when we explode with oxygen. One volume of
phosphuretted hydrogen requires, as nearly as I can find, 3½ of nitrous
gas for mutual saturation. The azote developed amounts to 1¾ volumes
or rather less, (due allowances in all such cases being made for that
already existing in the two gases.)
The mutual action of nitrous gas and phosphuretted hydrogen without
electricity exhibits one of the most singular phenomena we have in
chemistry. Nitrous gas seems constantly to be decomposed, one part
producing nitrous oxide and another part azote, even though an excess
of nitrous gas remain undecomposed in the mixture, and both the
phosphorus and hydrogen are completely burnt; but if the nitrous gas be
deficient, then nitrous oxide, azote, and some of the phosphuretted
hydrogen are found in the residue, and the rest of the phosphuretted
hydrogen is completely burnt or converted into phosphoric acid and
water; here appears no preference of phosphorus to hydrogen in this
case, nor any partial combustion. From an attentive consideration
of the results of several experiments, I am inclined to offer the
following solution of this remarkable case: One atom of phosphuretted
hydrogen attacks 5 of nitrous gas at the same instant; the atom of
phosphorus takes 2 of oxygen, and gives the corresponding 2 of azote
to the two of nitrous gas, and thus makes two atoms of nitrous oxide,
while the hydrogen takes 1 of oxygen from the fifth atom and liberates
the azote; thus 2 measures of nitrous oxide are formed along with 1 of
azote; and they are generally found in the residue in that ratio. The
azote does not seem to pass through the intermediate state of nitrous
oxide; for, as soon as the nitrous gas ceases to exist, there is an end
of the combustion.
It may be proper to advert more particularly to the hydrophosphoric gas
of Davy. That this gas is the same as that we have been describing,
can hardly admit of a doubt. Their near agreement in sp. gr., in
their absorbability by water, in the quantity of oxygen requisite
for their combustion, in their moderate expansion by burning with a
minimum of oxygen and in their combustibility by oxymuriatic acid, are
circumstances sufficient to warrant their identity. It is said that
by heating potassium in this gas, one volume yields two of hydrogen;
but it has not been found to yield two volumes by electricity, the
more accurate criterion. Besides, both Davy and Gay Lussac find that
potassium heated in the more common phosphuretted hydrogen expands
it from 1 to 1⅓ or 1½ volume, which common electricity will not do;
it is presumed therefore that the potassium in some way conduces to
the production of a portion of the hydrogen. Spontaneous ignition
or explosion is, I believe, no distinctive mark of variety in
phosphuretted hydrogen; when this gas is _produced_, it is usually
explosive from the uncombined phosphorus which it elevates; but the
best and purest phosphuretted hydrogen loses the property wholly or
partially by standing a while over water, though it loses no sensible
part of its phosphorus.
It is commonly stated that phosphuretted hydrogen deposits phosphorus
by long standing. This seems to be true; but the deposition is slower
than I imagined. Seven years ago I set aside a bottle of impure
phosphuretted hydrogen which I then labeled, 10 combustible take
14.6 oxygen; this bottle has not been preserved with special care to
seclude the atmosphere; notwithstanding that, it is now such, that 10
combustible take 6.7 oxygen, and hence it still contains some genuine
phosphuretted hydrogen.
2 _and_ 3. _Phosphurets of carbone and sulphur._
See VOL. 1. page 464.
_4. Phosphuret of lime._
This compound may be formed by subliming phosphorus in a glass tube
containing small fragments of recently calcined lime, heated to a low
red. The sublimed phosphorus coming into contact with the hot lime,
the two unite with a vivid glow, and in due time mutual saturation is
produced. The result is a dry, hard compound of a deep brown or reddish
colour, which on cooling must be put into a bottle and well corked, if
not intended for immediate use, as it soon changes by the action of
atmospheric air and moisture. With this precaution, I have reason to
think it may be kept unimpaired for years.
As far as I know, no experiments have been published relating to the
proportion in which phosphorus and lime unite. M. Dulong, in a valuable
paper on the combinations of phosphorus and oxygen, in the _Memoires de
la Société d’Arcueil_, VOL. 3. (1817,) has given some account of his
experiments on the earthy phosphurets; but it is to be regretted that
he has given none on the proportions of their elements.
In order to ascertain the phosphorus, I put 10 grains of well preserved
phosphuret of lime, into 1000 grains of liquid oxymuriate of lime, such
that by previous trials I knew would impart 3.5 grains of oxygen; to
this mixture a quantity of muriatic acid was put, sufficient to engage
the lime; the phosphuretted hydrogen disengaged, was of course made
to pass through the liquid as it was generated, and became oxidized,
so as to lose its gaseous form; the surplus gas was prevented from
escaping by an inclination of the bottle; it was 45 grain measures
only, and of this 30 were found to be pure hydrogen, and the rest
atmospheric air detached from the water; these 30 measures were the
_free_ hydrogen, which would have been mixed with the phosphuretted
hydrogen, in the ordinary way. In due time, the whole of the phosphuret
of lime was dissolved. The liquid was strongly acid, and manifested
no smell of oxymuriatic acid, a proof that it was all decomposed. To
this were added 70 more of the oxymuriate of lime before the smell of
it was permanently developed. The liquid was next saturated with lime
water, and the phosphate of lime carefully collected and dried; when
heated to a low red it weighed 12 grains, and consisted, according to
my estimate of this compound, of 6-- grains of phosphoric acid and
6 + grains of lime. The 6-- grains of acid contained 2.4 phosphorus
and 3.5 of oxygen. It must be remembered that 10 grains of phosphuret
yield about 500 measures of phosphuretted hydrogen, and these contain
650 measures of hydrogen, which last is also oxidized at the expence
of the oxymuriatic acid; but then there is an equivalent of oxygen
from the water, so that this does not influence the calculation for
oxygen. There appears then to be only an excess of .24 grains of oxygen
unaccounted for, (arising from the additional 70 of oxymuriate of
lime), which is as little as can be expected in such an experiment. If
the phosphorus amount to 24 per cent. we may reasonably infer that the
remainder (76) is mostly lime, though I have not been able to detect
above 60. Now if an atom of phosphorus weigh 9⅓ and one of lime 24, the
due proportion of the protophosphuret of lime would be 28 phosphorus
and 72 lime; but when the article is made for sale, it is more likely
to find a defect than an excess of phosphorus.
According to Dulong, when the earthy phosphurets are decomposed by
water, phosphuretted hydrogen and subphosphorous acid are formed. I
believe this determination is right; for I find at most only ⅓ of the
above proportion of phosphorus in the phosphuretted hydrogen yielded
by 10 grains of the phosphuret of lime; the remaining ⅔ seem to rest
in the liquid in combination with the oxygen and lime; that is, 1 atom
of hydrogen combines with 1 of phosphorus, and 1 of oxygen with 2 of
phosphorus. Notwithstanding this, the phosphoric acid produced from the
residue by means of oxymuriate of lime, does not in general correspond
to the above quantity. Perhaps this loss may be owing to the phosphorus
carried over in mechanical suspension by the gas.
M. Dulong observes, that even the earthy subphosphites are very
soluble; this did not appear to me to be the case with that of lime: 10
grains of phosphate of lime, that had been exposed for 20 minutes to
the air, were put into a gas bottle filled with 400 grains of water;
this was kept at nearly the boiling heat for an hour, when 725 grain
measures of gas were produced, and some phosphorus was carried over
with it into the receiving bottle and bason of water. The gas being
analysed, was found to consist of 62 per cent. phosphuretted hydrogen,
33 hydrogen and 5 common air. The 400 grains of water in the gas bottle
treated with oxymuriate of lime, and then with lime water, scarcely
gave any appreciable quantity of phosphate of lime. The insoluble
residue when dried yielded 9 grains. This dissolved in muriatic acid
left a fraction of a grain of dirty yellow powder, which indicated some
phosphorus; and the muriate of lime indicated about 6 grains of lime.
_5. Phosphuret of barytes._
The combination of phosphorus and barytes may be effected in the
same way as the foregoing, and the compound has the same appearance.
According to Dulong, who has examined this phosphuret with particular
attention, it gives out phosphuretted hydrogen when dropped into
water, the same as that of lime. When the gas ceases to be given out,
a powder remains completely insoluble in water, of a variable colour,
yellow, grey or brown. It is not altered by the air; but it gives out
a slight phosphoric flame when heated. Dilute nitric or muriatic acid,
dissolves nearly the whole with a trace of phosphuretted hydrogen,
and leaves only a few atoms of greenish yellow powder, soluble in
oxymuriatic acid. The part dissolved by the acids being precipitated
by ammonia, gives phosphate of barytes. From these facts he infers
that the residue insoluble in water, consists of a small portion of
phosphuret of barytes with excess of base, and phosphate of barytes.
The water in which the phosphuret was decomposed, contains most of the
barytes; carbonic acid produces a slight precipitate, and then leaves
a neutral liquid containing the subphosphate of barytes, which appears
to be a very soluble salt. Sulphuric acid throws down the barytes and
leaves the subphosphorous acid in the liquid.
Nothing certain is determined from experiment respecting the proportion
of phosphorus and barytes which combine; but from analogy it is
probable that they combine atom to atom, or 68 parts barytes with 9 of
phosphorus; or 100 parts of the compound contain 88 of barytes and 12
of phosphorus.
_6. Phosphuret of strontites._
Phosphuret of strontites may be formed as the two preceding articles.
It is in all respects similar to the phosphuret of barytes according to
Dulong, and its properties therefore need not be particularized.
From analogy, I should apprehend, it must be constituted of 46
strontites and 9 phosphorus, or one atom of strontites to one of
phosphorus; that is, 100 parts of phosphuret should contain 83
strontites and 17 phosphorus.
Combinations of the other earths and phosphorus have not yet been
effected. Neither have the alkalies been combined with phosphorus; the
hydrates of these as well as those of the earths, yield phosphuretted
hydrogen when heated with phosphorus, and probably a phosphate or
subphosphate of the base. M. Sementini of Rome is said to have
succeeded in combining potash and phosphorus by means of alcohol.
His experiments, however, appear to me too indefinite to warrant
the conclusion. (See An. of Philos.--7. p. 280). The compounds of
phosphorus with potassium and sodium are described in the sequel,
amongst the metallic phosphurets.
_7. Phosphuret of gold._
M. Pelletier heated together in a crucible, half an ounce of pure gold,
one ounce of phosphoric glass and ⅛ of an ounce of powdered charcoal,
the heat was raised sufficiently to fuse the gold. Phosphoric fumes
arose, but the whole of the phosphorus was not dissipated. The gold
remaining was whiter than natural, and brittle under the hammer.
Exposed to a very high heat it lost ¹/₂₄ of its weight, and resumed the
ordinary characters of gold.
The same chemist heated 100 grains of pure gold in filings to a bright
red; he then projected small fragments of phosphorus amongst the gold
successively till after it had entered into fusion. The gold preserved
its colour, but became brittle under the hammer and granular in the
fracture; it had increased 4 in weight.
Mr. Edmund Davy, by heating in a tube deprived of air, finely divided
gold and phosphorus, effected a combination of them. It had a grey
colour and metallic lustre. The heat of a spirit lamp was sufficient
to decompose it. It contained about 14 per cent. of phosphorus.
(Davy’s Chemistry, page 448--An. 1812).
Oberkampf and Thomson have successively observed the precipitation
occasioned by water impregnated with phosphuretted hydrogen, in
solutions of muriate of gold. The former of these has some interesting
remarks on the phenomena. When a current of this gas is passed through
a dilute solution of muriate of gold for a time, and then suddenly
discontinued, the solution becomes brown and passes soon to a fine deep
purple. A yellowish brown precipitate is obtained, which is metallic
gold, and the liquid, now become yellow again, contains muriate of gold
and phosphoric acid. The experiment may be continued with the like
results. But if the liquid be saturated with gas before any precipitate
is suffered to subside, a black powder is obtained which does not
seem to contain any metallic gold, and the liquor ceases to have any
colour. This black powder is the phosphuret of gold; exposed to heat it
inflames and leaves metallic gold, but its elements are not separable
by mechanical means. (An. de Chimie, 80--146, for 1811).
Water impregnated with the gas was found to have like effects as the
gas itself. Whence Oberkampf concludes that as long as an excess of
gold remains in solution, the phosphuretted hydrogen precipitates the
metal only; but when the gas is in excess, the phosphorus leaves the
hydrogen and unites with the precipitated gold.
I should rather suppose that the precipitation of the gold may be,
in part at least, owing to the _free_ hydrogen which we now know
accompanies the phosphuretted hydrogen largely, in the manner in which
this gas was formerly procured; however that may be, I find that water,
impregnated with the purest phosphuretted hydrogen, has the property
of precipitating the black phosphuret of gold from the muriate of
that metal, in such manner as to effect complete mutual saturation,
leaving nothing in the liquid but the muriatic acid. Let a solution
containing a known quantity of gold be gradually dropped into water,
containing a known quantity of phosphuretted hydrogen, as long as any
black precipitate is formed. The point of saturation will be found when
60 parts by weight of gold have united to 9 of phosphorus, nearly; or
when one atom of gold has united to one of phosphorus. Hence it may be
concluded that 100 grains of the phosphuret of gold contain 13 or 14
of phosphorus, which agrees very nearly with the results of Mr. Edmund
Davy abovementioned.
8. _Phosphuret of platina._
M. Pelletier succeeded in combining platina with phosphorus by the same
methods as with gold. By projecting phosphorus on grains of platina
heated to a strong red, the latter acquired an increase of weight of
18 on the hundred; but this was probably an excess, as some vitreous
phosphoric acid was found mixed with the mass.
In the Philos. Magazine, VOL. 40, Mr. E. Davy has related some
experiments made with a view to combine platina and phosphorus; he
effected it by heating platina and phosphorus together in an exhausted
tube; the union commenced below a red heat and was attended with vivid
ignition and flame. The compound was of a blueish grey colour and
consisted of 82½ platina and 17½ phosphorus according to his estimate.
Also by heating the ammonia-muriate of platina with ⅔ of its weight of
phosphorus in a retort over mercury, muriatic gas was liberated, and
muriate of ammonia and phosphorus were sublimed, but there remained at
dull red heat an iron black or dark grey mass at the bottom, of the sp.
gr. 5.28. It was estimated to consist of 70 platina and 30 phosphorus;
but I doubt whether it could consist of these two elements only.
Phosphuretted hydrogen water scarcely has any effect on muriate of
platina. After some time a very light flocculent matter appears, as
Dr. Thomson has observed; but this seems to me to be nothing but a
slight precipitation of phosphorus alone; I apprehend the gas unites
with the platina, but the compound remains in solution somewhat in the
same manner as platina and sulphuretted hydrogen. The platina may be
precipitated from the clear liquid by muriate of tin, much the same in
appearance as if no phosphuretted hydrogen were present.
9. _Phosphuret of silver._
When pieces of phosphorus are dropped amongst silver heated to red in a
crucible, the two unite and enter into fusion, according to Pelletier;
when the metal is saturated with phosphorus the whole continues in
a state of tranquil fusion; but being withdrawn from the fire, at
the moment of congelation, a quantity of phosphorus becomes suddenly
volatile and burns vividly, and the surface of the metal becomes
uneven. The metal on being cooled, is found to have gained from 12 to
15 per cent.; and he apprehends that when fluid it contains 10 per
cent. more, making in all 25 phosphorus to 100 silver.
The phosphuret of silver is white and crystalline, brittle under the
hammer, but capable of being cut with a knife. By a strong heat the
phosphorus is dissipated and leaves the silver pure.
Both Raymond and Thomson observe that phosphuretted hydrogen water
precipitates silver from its solutions of a black colour. I find that
a solution of sulphate of silver containing one grain of the metal,
requires water containing 90 grain measures of phosphuretted hydrogen
to saturate it; the whole of the silver falls readily and leaves
nothing but the acid in the water. Now the weight of 90 measures of
this gas is nearly ⅑ of a grain; hence the proportions of metal and
phosphorus are as 10 to 1, which shows that they combine atom to atom,
or 90 silver to 9⅓ phosphorus. This is somewhat less of phosphorus than
is determined above by Pelletier.
10. _Phosphuret of mercury._
M. Pelletier made several attempts to combine phosphorus and mercury.
He seems to have succeeded best, by exposing mercury in an extreme
state of division, to phosphorus under water in a moderate heat. The
phosphuret is a black compound, which is resolved again into its
elements by distillation.
When nitrate of mercury is treated with phosphuretted hydrogen water, a
copious dark brown or black precipitate is instantly formed, as Raymond
and Thomson have observed. This black precipitate, Raymond adds, soon
becomes white and crystalline in passing from phosphuret to phosphate,
by attracting oxygen.
I have found the black powder when dried in a moderate heat to abound
in small shining globules, which have all the appearance of revived
mercury. However this may be, I find that a certain weight of mercurial
salt requires a certain portion of gas to saturate it, so as that the
whole mercury shall be precipitated. One grain of mercury requires
rather more than ¹/₁₈ of its weight or 50 grain measures of the gas
for its saturation. This proves the combination to be the most simple,
or atom to atom; that is, 167 mercury take 9⅓ phosphorus; or 100
mercury take 5½ phosphorus nearly.
11. _Phosphuret of palladium._
When nitrate of palladium is dropped into phosphuretted hydrogen water,
a copious black flocculent precipitate is immediately formed, which
doubtless consists of palladium and phosphorus.
Into 800 grains of phosphuretted hydrogen water containing 20 grain
measures of gas, were put by degrees, 22 grain measures of muriate
of palladium (sp. gr. 1.01) containing .12 acid and .14 oxide,
corresponding to .12+ metal; mutual saturation was produced, and a
finely distinct black powder precipitated, leaving the water clear
and colourless, which was found by lime water to contain .12 parts
of a grain of muriatic acid. The black powder collected and dried,
corresponded as nearly as could be determined in weight to the
ingredients. Now 20 measures of gas would weigh .025 of a grain, of
which .0025 would be hydrogen and .0225 phosphorus; whence we have
.12+ metal joined to .0225 phosphorus or 50 to 9 nearly, indicating
one atom of each. Hence 100 palladium would take 18 or 19 phosphorus.
12. _Phosphuret of copper._
M. Pelletier combined copper and phosphorus by the same means as the
preceding compounds. One hundred grains of copper united by heat with
15 of phosphorus; the fused mass when cooled was white and very hard.
As part of the copper gets oxidized during the process he thinks
it probable, with M. Sage, that copper may acquire 20 per cent. of
phosphorus.
In the 3d VOL. of Memoirs of the Society of Arcueil, page 432, M.
Dulong converts fine copper wire into phosphuret by heating it to a
low red, and passing the vapour of phosphorus over it in hydrogen gas.
In the sequel he observes that 10 grammes of phosphuret of copper
contained 1.97 of phosphorus; that is, the copper was to the phosphorus
as 8.03 ∶ 1.97, or as 100 ∶ 24.5. This exceeds much Pelletier’s result,
and is, I think, too high. For, he found that the above phosphuret
converted into phosphate of copper by nitric acid yielded 14.44
grammes. Now supposing the atom of phosphorus to weigh 9⅓, that of
phosphoric acid 23⅓, and that of the black oxide of copper 70, we have
an atom of phosphate of copper = 93⅓: and if 93⅓ ∶ 9⅓ ∷ 14.44 ∶ 1.444,
for the phosphorus in 10 grammes; and hence the copper would be 8.556:
this would give 100 copper to 17 phosphorus nearly, which would accord
well with Pelletier’s determination, and very nearly agree with the
theoretic result of 100 copper to 16⅔ phosphorus.
Both Raymond and Thomson remark that phosphuretted hydrogen water
produces a black or dark brown precipitate in sulphate of copper. I
have not found any precipitate from any of the salts of copper by the
same means. But if the blue hydrate be first precipitated by lime
water, and then the phosphuretted hydrogen water admitted, the hydrate
is immediately converted into a dark olive, which in all probability is
a phosphuret of copper. From some experiments I am inclined to believe
that this compound is the deutophosphuret, or two atoms of phosphorus
to one of copper; and hence the copper is to the phosphorus as 100 ∶
33⅓.
13. _Phosphuret of iron._
M. Pelletier formed a phosphuret of iron by both the methods above
described for gold. He describes the phosphuret as very hard, of
a white colour, striated and magnetic. He estimates, with some
uncertainty, that 100 iron may combine with 20 phosphorus.
Berzelius produced a phosphuret of iron by reducing the phosphate
of the metal by charcoal and heat. (An. de Chimie, July 1816). He
describes it as having the colour of iron, brittle and slightly acted
upon by the magnet. By his analysis it was constituted of 100 iron and
30 phosphorus. The true proportion probably would be one atom to one,
or 25 iron to 9⅓ phosphorus; that is, 100 iron to 37 phosphorus.
Both Raymond and Thomson found that sulphate of iron yields no
precipitate by phosphuretted hydrogen water; and I may add, that the
precipitated oxide or hydrate is also unaffected by the same.
14. _Phosphuret of nickel._
By projecting phosphorus amongst red hot nickel, Pelletier united 20
parts of the former to 100 of the latter. A part of the combined
phosphorus, he observes, flies off on cooling, so that the above
proportion may perhaps be too low. Theoretically one atom of nickel
should combine with one of phosphorus; that is, 26 with 9⅓, or 100 with
36.
I find that neither the nitrate of nickel nor the hydrate are affected
by phosphuretted hydrogen water.
15. _Phosphuret of tin._
Margraff was the first who combined phosphorus and tin by fusing the
metal along with fusible salt from urine (phosphate of ammonia).
Pelletier succeeded also in this way, as well as by the direct one of
projecting phosphorus into melted tin. The compound was of a white
colour; it gained 12 per cent. of weight; but as part of the tin was
oxidized and adhered to the crucible in form of glass, he conjectures
that tin would take from 15 to 20 per cent. of phosphorus. The atom of
tin being 52, and that of phosphorus 9⅓, the due proportion would be
100 tin to 18 phosphorus.
Phosphuretted hydrogen water does not seem to precipitate tin from
solutions, nor yet to act upon the precipitated oxide.
16. _Phosphuret of lead._
Lead combines with phosphorus by the same methods as tin; but it is
difficult to ascertain the proportions, according to Pelletier, from
the oxidation and vitrification of part of the lead. Muriate of lead
distilled with fusible salt of urine, also yielded phosphuret of lead.
He conjectures the increase by phosphorus to be 12 or 15 per cent.; but
by theory it should only be 10 or 11 per cent.
Raymond says that the nitrate of lead is decomposed by phosphuretted
hydrogen water, but with less force than salts of silver and mercury;
and that a phosphuret of lead is formed, of which he gives no
character, except that it becomes in time a phosphate. Thomson says a
slight white powder is formed by the mixture. This was the case with
me; but I suspected that the white powder was merely a little sulphate
of lead, arising from the impurity of the (rain) water; and this was
found to be the fact; for the milkiness was just the same with like
water unimpregnated with the gas. Besides, after the phosphuretted
hydrogen water has been saturated with nitrate of lead till no more
effect is produced, still the water retains its peculiar smell, and a
copious black precipitate is instantly produced by nitrate of silver or
mercury. It appears then that phosphuret of lead cannot be formed this
way. Neither does phosphuretted hydrogen water seem to have any effect
on the recently precipitated oxide of lead.
17. _Phosphuret of zinc._
Both zinc and its oxide seem to combine with phosphorus, according to
Pelletier; but the proportions were not ascertained. By theory, zinc
should take 32 per cent. of phosphorus.
18. _Phosphuret of potassium._
Some account was given by Davy, of the combination of potassium and
phosphorus in essays from 1807 to 1810; and by Gay Lussac and Thenard
in others from 1808 to 1811. According to Davy, when potassium and
phosphorus are heated together, they combine in one uniform ratio of 8
to 3 nearly; and the compound, when acted upon by muriatic acid, gives
out from .8 to 1 cubic inch of phosphuretted hydrogen gas, resulting
from one grain of the former and ⅜ of a grain of the latter substances
combined. Also be observed that half a grain of potassium decomposed
nearly 3 cubic inches of phosphuretted hydrogen, and set free more than
4 cubic inches of hydrogen; the phosphuret seemed to be of the same
kind as the former, or that by direct combination of the two elements.
Gay Lussac and Thenard combined the elements by heat; the potassium is
scarcely fused till the phosphuret is formed. The excess of phosphorus
sublimes, and the phosphuret is always of a chocolate colour; the
proportions were not ascertained. By treating this phosphuret with
warm water, a quantity of phosphuretted hydrogen was uniformly given
out, about 40 per cent. more than the hydrogen which would have been
yielded by the potassium alone in water. But if the phosphuret was
treated with dilute acid instead of water, then less gas was given out
than otherwise; and the stronger the acid the less gas, so as sometimes
to reduce the gas in volume to that yielded by potassium alone. They
also found, as Davy had done, that potassium heated in phosphuretted
hydrogen decomposed it, uniting with the phosphorus and producing the
same compound as in the direct way.
The results of Davy and the French chemists appear to be discordant;
but I apprehend they may be reconciled. It appears probable from both,
that the phosphuret of potassium must be a compound of one atom of
each, or 35 potassium and 9⅓ phosphorus; that is, 100 potassium and
27 phosphorus nearly. Now in Davy’s method of treating the compound
with acid, it is most probable that the atom of potassium takes one
of oxygen to form potash, and the atom of phosphorus takes one of
hydrogen to form one of phosphuretted hydrogen; but 3 volumes of pure
phosphuretted hydrogen contain 4 volumes of hydrogen, (see page 178);
and Davy obtained nearly ¾ of the volume of gas which the potassium
alone would have produced, which therefore accounts for the fact as
stated by him.
On the other hand, the French chemists by treating the phosphuret
with hot water, probably determined the resolution in this way: the
potassium resolved the water into oxygen and hydrogen the last of which
was liberated in a free state, and of course produced the usual volume;
the phosphorus also resolved the water into oxygen and hydrogen, one
half of it taking the oxygen to form phosphorous acid, and the other
half taking the hydrogen to form phosphuretted hydrogen, which of
course would produce phosphuretted hydrogen amounting to ⅜ of the
volume of free hydrogen or 38 per cent. nearly, which would make up
the volume of gas to 138, or nearly 140, as observed by them. It is
not unlikely that 2 or 3 per cent. of hydrogen might be added by the
further decomposition of water by the phosphorous acid, in order to
make it into phosphoric acid.
19. _Phosphuret of sodium._
No particular experiments having been detailed of this compound, we
must infer it is similar to the last mentioned, and consists of one
atom of sodium, 21, and one atom of phosphorus, 9⅓; that is, 100 sodium
and 44 phosphorus nearly.
20. _Phosphuret of bismuth._
If we may judge from M. Pelletier’s experiments, bismuth has but a weak
affinity for phosphorus. By projecting portions of phosphorus amongst
melted bismuth, he succeeded in uniting some of it to the metal; he
estimates the quantity at 4 per cent.; whereas by theory it ought to be
15 per cent. supposing them to unite atom to atom.
I do not find that the salts or oxide of bismuth are materially
affected by phosphuretted hydrogen water.
21. _Phosphuret of antimony._
Phosphorus may be combined with antimony, according to Pelletier, by
the same means as with the other metals. The phosphuret has a white,
metallic appearance and lamellar fracture. The ratio of the elements
was not determined. By theory supposing one atom to unite with one, it
would be 40 to 9⅓, or 100 antimony to 23 phosphorus nearly.
Phosphuretted hydrogen water seems to have no effect on the salts or
oxide of antimony.
22. _Phosphuret of arsenic._
From the experiments of Margraff and Pelletier, it seems probable
that phosphorus unites both with arsenic and its oxide. By distilling
a mixture of equal parts of arsenic and phosphorus in a carefully
regulated heat, Pelletier obtained a residuum of a black shining
substance, containing a good proportion of phosphorus. The same was
obtained in the humid way, by keeping phosphorus in fusion on arsenic
under water for some time. The phosphuretted oxide may be obtained by
distilling phosphorus and the white oxide of arsenic together, the
phosphuretted oxide sublimes mixed with arsenic and phosphorus in a
separate state. It is of a red colour. The proportions in neither case
were ascertained. It is probable that the compounds are of the most
simple kind, or one atom to one; in that case we shall have 21 arsenic
and 9⅓ phosphorus, or 100 arsenic and 44 phosphorus for phosphuret of
arsenic; and 28 oxide and 9⅓ phosphorus, or 100 oxide and 33 phosphorus
for phosphuretted oxide.
No precipitation is occasioned by phosphuretted hydrogen water in
solutions of arsenic.
23. _Phosphuret of cobalt._
Cobalt unites with phosphorus in the direct way as well as by being
heated with phosphoric glass. The colour of the compound is a blueish
white; it is brittle and crystalline in the fracture. The metal
acquires 7 per cent.; this is below the theoretic quantity, which is 25
per cent. if the atom of cobalt be 37.
Solutions of cobalt give no precipitate by phosphuretted hydrogen water.
24. _Phosphuret of manganese._
This compound may be formed like the preceding ones. It is of a white
colour, brittle and of a granular texture. It is not liable to be
altered by the air like the pure metal. The proportions of the compound
Pelletier did not determine. Reasoning from theory, it should consist
of 25 metal and 9⅓ phosphorus; or 100 metal and 37 phosphorus.
The salts and oxide of manganese are not sensibly affected by
phosphuretted hydrogen water.
* * * * *
The combinations of the remaining metals with phosphorus can scarcely
be said to have been investigated.