A Comprehensive Treatise on Inorganic and Theoretical Chemistry

PLATINUM 307
minochloroplatinite in a boiling soln. of platinic chloride ; P. T. Cleve, by mixing
boiling soln. of platinic dichlorotetramminochloride and potassium chloroplatinite ;
P. T. Cleve, and A. Cossa, by mixing soln. of platinic chloride and of platinous
tetramminochloride ; and C. Gerhardt, by the action of chlorine on platinous
tetramminochloroplatinate. The reddish-brown, crystalline powder is sparingly
soluble in water ; and with silver nitrate, it precipitates silver chloride, and forms
platinic hydroxychlorotetramminonitrate. C. Gerhardt obtained platinic dichlorotetramminochloroplatinate,
[Pt(NHg)4Cl2]PtCl6, by passing chlorine into water
with platinous tetramminochloroplatinite in suspension ; C. Grimm, by passing
chlorine into a soln. of platinous tetramminochloride ; and P. T. Cleve, by mixing
sodium chloroplatinate with platinic dichlorotetramminonitrate. The crystals
are quadratic plates or octahedra, -with the colour of potassium dichromate ; they
do not lose weight at 100° ; and when boiled a short time with silver nitrate,
precipitate three-quarters of the contained chlorine as silver chloride.
E. A. Hadow prepared- platinic hydroxychloro tetramminochloride,
[Pt(NHg)4(OH)Cl]Cl2, by mixing a hot cone. soln. of the corresponding nitrate
with an excess of ammonium chloride ; he considered it to be a hemihydratc, but
P. T. Cleve observed that the salt is anhydrous when dried at 100°. C W. Blomstrand,
P. T. Cleve, and W. Odling discussed the constitution. The snow-white
precipitate consists of rhombic prisms, sparingly soluble in water.
P. T. Cleve obtained platinic trichlorotriamminochloride, [Pt(NH3)3Cl3]Cl,
in pale yellow, rhombic or hexagonal plates by boiling platinous nitratotriamminonitratc
with aqua regia, and drying the crystalline product at 100°. A. Werner
and A. Miolati found that the mol. conductivities of soln. of a mol of the salt
in 500, 1000, and 2000 litres are, respectively, 91-43, 96-75, and 106-5. The conductivity
of the first-named soln. changed to 97-5 in 3 hrs. and to 106-5 in 24 hrs.
C. Gerhardt prepared platinic Amn.s-tetracMorodiaminine, f Pt(NH3J2Cl4],
by passing chlorine into boiling water with platinous ifran.v-dichlorodiammine
in suspension until the pale yellow salt becomes lemon-yellow and a drop of the
liquid forms yellow crystals on cold glass. C. Grimm employed a similar process,
and P. T. Cleve, and W. Odling employed aqua regia or potassium permanganate
as oxidizing agents in place of chlorine ; and L. A. TschugaefT and W. Chlopin, ozone
in hydrochloric acid soln. S. M. Jorgensen oxidized a boiling hydrochloric acid
soln. of platinous £raw..s-bispyridinediamminochloride with potassium permanganate,
and allowed the soln. to cool slowly. W. Lossen, and H. Alexander obtained the
salt as a by-product in the preparation of hydroxylamine hydrochloride in the
mother-liquor remaining after the removal of ammonium chloride by platinic
chloride ; and F. Hoffmann observed that it is formed when platinic ci«s--dihydroxylaminediamminochloride
is boiled with hydrochloric acid. The nature of the compound
was discussed by E. Gapon, C. Weltzien, C. Gerhardt, W. Odling,
S. H. C. Briggs, S. M. Jorgensen, and A. Werner and co-workers. The lemonyell
ow, crystalline powder consists of octahedral or quadratic plates. According to
E. G. Cox and G. H. Preston, the crystals of the a-salt are lemon-yellow, tetragonal
—sometimes bipyramids—usually tabular on the (OOl)-face ; and the X-radiograms
corresponded with a cell having a—5-72 A., c=10-37 A., and 2 mols. per unit
cell, so that the calculated sp. gr. is 3-61, and the observed result is 3-3. Each
ammonia group in the cell is surrounded by 8 chlorine atoms, belonging to its own
or adjoining molecules, and each chlorine atom is surrounded by 4 ammonia mols.
TheyS-salt forms lemon-yellow rhombic plates tabular on the (010)-face and bounded
by the (lOl)-face or the (lOO)-face. The crystals are sometimes distorted. The
cell dimensions are a== 10-0 A., 6=11'2 A., and c=6-0 A. There are four molecules
per unit cell, and the calculated sp. gr. is 3-6, when the found value is 3-3.
P. T. Cleve observed that the crystals begin slowly to decompose at 200° to 216°,
and F. Hoffmann added that no explosion occurs. E. Petersen observed that a
mol of the salt dissolved in 250 litres of water depressed the f.p. 0-028° ; and
A. Werner and A. Miolati observed that the electrical conductivity of the soln.