A Comprehensive Treatise on Inorganic and Theoretical Chemistry

PLATINUM 333
M. Slondel also obtained an oxychloroplatinate by adding sodium hydroxide to a dil.
soln. of sodium chloroplatinate at 100° so that the soln. remains acidic. In. this way.
5 mols. of sodium hydroxide can be added per mol. of hydrochloroplatinic acid without
reversing the acidity of the liquid. After dialysis, a product is formed with variable proportions
of platinum, sodium, and chlorine. E. Johannsen obtained various calcium
oxychloroplatinates by the action of calcium hydroxide on soln. of hydrochloroplatinic
acid ; and F. "Weiss and F. Dttbereiner, and E. Johannsen, various barium ovcyehloroplatinates
by the action of barium hydroxide on that acid.
S. M. Jorgensen obtained some chromic hydroxychloroplatinates : chromic hydroxydecammlnochloroplatinate,
[Cra(OH)(NH3)10]2(PtCl6)6.10H:aO, and [Cra(OU)(NH8)10laCl4-
(PtCl6J3 ; chromic trihydroxyaquohexamminochloroplatinate, [Cr8(OH)8(NHa)6],(PtCl,)8.4Hi!0,
and tCra(OH)3(HaO)(NHs)6]Cl(PtCle).HaO ; G. Vortmann and O. Blasberg, cobaltic hydroxyehlorooctamminochloroplatlnate,
2Co(OH)Cla.PtCl4.8NH3.HaO ; F. A. Genth, ammonium
eobaltic hydroxytrlamminochloroplatinate, 3NH4Cl.Coa(OH)3Cla.2PtCl4.3]SrH3 ; and G. Vortmann,
3NH4C1.2Co(OH)aC1.2PtCl4.7NH4.3HaO—vide infra.
Hydroxychloroplatinic acids.—A series of acids has been reported with the
general formula H2PtCl6_n(OH)n. A. Miolati and I. Bellucci, and I. Bellucci prepared
pentahydroxychloroplatinic acid, H2Pt(OH)5Cl, by the action of cold
0-IiV-H2SO4 on the corresponding barium salt. The brown, deliquescent syrup
is a dibasic acid ; it reacts with carbonates, slowly in the cold, rapidly when warmed.
S. M. Jorgensen reported the corresponding anhydride dioxyhydroxychloroplatinic
acid, H2PtO2(OH)Cl, to be probably formed when an aq. soln. of equimolar parts
of platinic chloride and ammonia is evaporated to dryness, extracted with water,
the filtered soln. treated with another molar part of ammonia, and then evaporated
on the water-bath.
I. Bellucci, and A. Miolati and I. Bellucci prepared silver pentahydroxychloroplatinate,
Ag2Pt(OH)5Cl, in brown flakes, by adding an excess of silver acetate
to a soln. of the corresponding barium salt, and drying the washed precipitate over
calcium chloride. K. Johannsen, and J. E. W. Herschel prepared calcium pentahydroxychloroplatinate,
CaPt(OH)5CLH2O, by mixing hydrochloroplatinic acid
with an excess of lime water in sunlight or violet light. The mixture remains clear
in darkness. E. Johannsen, and A. Miolati and I. Bellucci used a somewhat
similar process. A. Miolati, I. Bellucci, A. Miolati and I. Bellucci, and P. Klason
discussed the nature of this salt. The white or yellowish-white powder can be
obtained as tabular crystals. J. W. Dobereiner observed that at a red-heat,
the salt loses 25 per cent, of water and oxygen to form a residue of calcium oxide
and chloride, and platinous oxide. The salt is insoluble in water ; soluble in
hydrochloric and nitric acids ; silver nitrate precipitates from the acidic soln. an
orange-yellow piecipitate ; the nitric acid soln. with ammonium chloride was
found by E. Weiss and E. Dobereiner slowly to form a precipitate of ammonium
chloroplatinate, E. Johannsen observed that the salt is slowly decomposed in the
presence of water and carbon dioxide. I. Bellucci, and A. Miolati and I. Bellucci
prepared strontium pentahydroxychloroplatinate, SrPt(OH)5CLH2O, by a process
analogous to that used for the calcium salt. A. Miolati also obtained barium
pentahydroxychloroplatinate, BaPt(OH)5CLnH2O. E. Johannsen also prepared
this salt ; and A. Miolati and I. Bellucci obtained the monohydrate. I. Bellucci,
and A. Miolati and I. Bellucci prepared mercuric pentahydroxychloroplatinate,
HgPt(OH)5Cl, by treating an acetic acid soln. of the barium salt with
mercuric acetate ; and similarly with thallous pentahydroxychloroplatinate,
TlPt(OH)5Cl ; but with lead acetate a basic lead pentahydroxychloroplatinate,
Pb(OH)2.PbPt(OH)5Cl, is formed.
A. Rosenheim and W. Lowenstamm obtained pale yellow dihydroxytetrachloroplatinic
acid, H2Pt(OH)2Cl4^H2O, or oxytetrachloroplatinic acid, H2PtOCl4.4H20,
by allowing a soln. of platinic chloride to stand exposed to the atm. for some time.
The acid was obtained by S. M. Jorgensen, W. Pullinger, and S. A. Norton by the
action of hot water on silver chloroplatinate. The soln. is evaporated and heated
to 100° when H2PtOCl4 is formed, but a further dehydration cannot be effected
without decomposing the compound. The aq. soln. has an acidic reaction, and