A Comprehensive Treatise on Inorganic and Theoretical Chemistry

254 INORGANIC AND THEORETICAL CHEMISTRY
E. Beckmann and W. Gabel found that platinous chloride is soluble in quinoline.
H. Rose found that oxalic acid gives no precipitate with soln. of platinous salts.
W. Eidmann found that the salt is insoluble in acetone ; J. J. Berzelius, that an
aq. soln. of potassium hydroxide converts it into hydrated platinous oxide and
potassium chloride. H. Rose added that potassium hydroxide does not act on soln.
of platinous salts, and that potassium or sodium carbonate gives a dark brown precipitate.
F. Miiller and A. Riefkohl studied the solubility in 2JV-soln. of sodium
chloride. IJ. Kugheimer and E. Rudolfi found that the chloride is soluble in a soln.
of bismuth chloride. G. Mazzaron found that platinum chloride gives chlorine
not chromyl chloride when treated with potassium dichromate and sulphuric acid.
Two compounds of platinous chloride with hydrochloric acid have been reported.
L. F. Nilson said that platinous hydrotrichloride, PtCl2.HC1.2H20, is formed
by decomposing barium chloroplatinite with the theoretical quantity of sulphuric
acid ; evaporating the filtered liquid first at 50°, and then in vacuo ; and drying
the product over sulphuric acid and potassium hydroxide in vacuo. The dark
brown, amorphous mass gives off water and hydrogen chloride at 100°.
I. IJ. Kondakoff and co-workers, and Hi. F. Nilson said that the aq. soln. contains
hydrochloroplatinous acid. C. Liebermann and C. Paal obtained salts with organic
bases ; and some am mines have been prepared—vide infra. Platinous hydrotrichloride
loses a mol. of hydrogen chloride in vacuo at 100°, and with a protracted
exposure some water is also given off. P. Klason said that platinous hydrotrichloride
is not a chemical individual, but rather a mixture of platinum dichloride
and tetrahydrated hydrochloroplatinous acid.
J. J. Berzelius, L. N. Vauquelin and G. Magnus dissolved platinous chloride
in boiling hydrochloric acid with exclusion of air. The soln. dried in vacuo furnishes
platinous dihydrotetrachloride, PtCl2.2HCLnH2O, or, according to P. Klason,
hydrochloroplatinous acid, H2PtCl4.4H2O. J. Thomsen showed that a soln. of
this salt can be obtained by treating a hot, sat. soln. of potassium chloroplatinite
with the theoretical quantity of hydrochloroplatinic acid, and filtering from the
precipitated potassium chloroplatinate. The heat of formation is (Pt,Cl2,2HCl, Aq.)
=41-83 CaIs. ; and (Pt,0,4HCl,Aq.)=31-55 CaIs. L.. Pigeon did not obtain satisfactory
results by reducing hydrochloroplatinic acid with sulphurous acid since
it is difficult to determine whether the reduction has gone too far, or not far enough ;
but he obtained a soln. by treating a soln. of a mol. of hydrochloroplatinic acid
with a mol. of dry barium carbonate, and a mol. of barium dithionate with 3 times
its weight of hot water, heating the mixture on a water-bath at 100°, and filtering
the liquor. L. F. Nilson heated hydrochloroplatinic acid on a sand-bath at 300°
until the dish and contents had the weight required for platinous chloride. The
unconverted platinum tetrachloride was extracted with hot water, and the residue
dissolved in hot, cone, hydrochloric acid. L. Pigeon said that the soln. cannot
be crystallized, and he preferred to convert it into potassium chloroplatinite by the
addition of potassium chloride.
L. N. Vauquelin observed that on evaporating the soln., brown platinous
chloride is formed. IJ. F. Nilson, and A. Miolati and U. Pendini recommended
evaporating the soln. first at 50°, and then in vacuo, and drying the product
over sulphuric acid and potassium hydroxide in vacuo. L. Wohler and F. Martin
found that the salt is stable in hydrochloric acid soln. ; no separation of platinum
was observed after it had been heated 10 hrs. in a sealed tube. If hydrochloric
acid be not in excess, the soln. readily forms platinum and hydrochloroplatinic
acid. It is supposed that the hydrochloroplatinous acid forms hydrodichloroxyplatinic
acid, H2PtOCl2, which then decomposes into platinum and platinic chloride,
PtCl4.H2O. Whilst solid platinous chloride can be heated to 600° or 700° in chlorine
for many hours at atm. press., the salt decomposes when the aq. soln. is heated
in a sealed tube at 120°. T. Curtius and J. Rissom observed that a soln. of
potassium azide furnishes brownish-red potassium azidoplatinite. Li. N. Vauquelin
observed that sodium hydroxide precipitates from the soln. hydrated platinous