A Comprehensive Treatise on Inorganic and Theoretical Chemistry

318 INORGANIC AND THEORETICAL, CHEMISTRY
acid deposits the salt on cooling. P. Schottlander observed that with sodium
thiosulphate, there is formed a complex between sodium thiosulphate, and platinum
sulphite. R. Fresenius found that the salt is very slightly soluble in aq. ammonia
in the cold, but it readily dissolves in the hot liquid, forming, according to
N. W. Fischer, a colourless or pale yellow liquid. The ammoniacal soln. is stable
in closed vessels, but when exposed to air, or when evaporated, it deposits a greyishwhite
precipitate ; and a precipitate is also formed when the ammoniacal soln. is
KiO. 80.—Tho System : !Fid. 81. The Solubility of Ammonium
(NH4)2l*tClfl~ (ISTH^)8IrCl0-H2O. chloroiridate in tho presence of tho
chloroplatinate.
treated with cone, acids—phosphoric, sulphuric, nitric, or hydrochloric—with
alkali carbonates, phosphates, sulphates, and oxalates, and with ferrous sulphate.
A. Laurent and C. Oerhardt found that alcohol precipitates from the ammoniacal
soln. a white amorphous mass approximately N4II10PtCl2-—but the composition
is not constant. J. J. Bcrzelius, and W. Knop noted that when ammonium chloroplatinate
is digested with aq. ammonia, a pale greenish-yellow powder is formed,
containing, probably, some [ Pt(NII3)4 JPtCl4. R. Bottger observed that a cone,
soln. of ammonium chloride precipitates the salt almost completely from its aq.
soln., and JI. St. C Deville and J. S. Stas said that the salt is sparingly soluble
in a cold, sat. soln. of ammonium chloride, and that the yellow soln. slowly becomes
colourless in contact with the chloroplatinate, or when warmed to 100°.
N. W. Fischer observed that the salt crystallizes out on cooling a soln. in hot
nitric acid. I. I. ShukofE and O. P. Schipulina found that the salt decomposes
when absorbed on charcoal. For the reduction by carbon monoxide, vide supra,
colloidal platinum. The salt is insoluble in ether, and in absolute alcohol.
R. Fresenius studied the solubility in alcohol. J. Dalietos and K. Makris found
alcohol vapour is oxidized by sodium but not by potassium chloroplatinate.
According to R. Fresenius, at 15° to 20°, 1 part of the salt dissolves in 26,535 parts
of 97-5 per cent, alcohol, in 1-476 parts of 76 per cent, alcohol, and 66-5 parts of
55 per cent, alcohol. If free hydrochloric acid is present, 1 part of the salt dissolves
in 76 per cent, alcohol. O. Dopping found that the salt is soluble in a soln. of
ammonium succinate ; and C. Claus, very soluble with decomposition in a soln.
of potassium thiocyanate. W. Knop observed that the salt is soluble in a soln.
of sodium hydroxide ; and E. von Meyer added that a large excess of potassium
hydroxide liberates an atom of nitrogen per mol. in the form of ammonia, and with
a smaller proportion of potassium hydroxide less nitrogen is so evolved. Fulminating
platinum is one of the chief products of the action. N. W. Fischer observed
that the salt is soluble in a soln. of stannous chloride ; and J. B. Rogojsky, that it
is less soluble in a soln. of hydrochloroplatinic acid than it is in water.
M. Zi. Huggins prepared tetramethylammonium chloroplatinate, (CHg)4NPtCl6,