This most valuable bleaching agent is a contraction of hydrogen and
oxygen, of the formula HO_{2}, sp. grv. 1.45 (chemically given), or
94.12 per cent. oxygen with 5.88 per cent. hydrogen. It consists in a
limpid, syrupous liquid, of characteristic color, and when heated to
15° C., is decomposed into water and oxygen, upon which property its
great bleaching power is based. Experiments to reduce it to a solid
form by refrigeration and pressure have thus far been unsuccessful.
The commercial article is somewhat modified by the addition of water
to prevent its ready decomposition under the influence of a warm
temperature. For the same reason it is advisable to always keep it in a
cool place.