A Comprehensive Treatise on Inorganic and Theoretical Chemistry

PLATINUM 117
per sq. cm., and the current yield is 60 to 7O per cent. At the anode, dissolution
of platinum begins at E—\ volt ; chlorine begins to be evolved at 1*2 to 1*4 volts.
W. Hittorf said that the platinum deposited electrolytically from a soln. of alkali
chloroplatinate is produced at the cathode by the reducing action of the alkali
metal. Observations were also made by W. Halberstadt, H. Danneel, A. Classen,
P. K. Frolich and G. L. Clark, E. R. Thews and R. W. Harbison, A. R. Powell
and co-workers, E. F. Smith, E. F. Smith and H. F. Keller, L. Schucht, F. Wohler,
A. JoIy and E. Leidie, J. W. Langness, P. Haas, C. W. Keitel and H. E. Zschiegner,
S. Popoff and A. H. Kunz, D. McDonald, F. Braun, and A. Coehn. E. Liebreich
found that in depositing platinum on silver in a soln. of nickel sulphate, platinum
shows a slight reaction just prior to the evolution of hydrogen.
A. C. and E. Becquerel found a difficulty in obtaining a smooth deposit, but by
using a dil. soln. of the chloride acidified with sulphuric acid, F. Rudorff, and
H. Freudenberg obtained a dull deposit which could be polished with sand.
A. Classen employed a hot soln. of the chloride acidified with sulphuric or hydrochloric
acid, or mixed with ammonium or potassium oxalate ; C. Luckow used a
dil. soln. of platinic chloride mixed -with sodium chloride ; W. Halberstadt, a warm
soln. of platinic bromide acidified with hydrobromic acid ; and E. F. Smith used
a soln. of ammonium chloroplatinate mixed with some sodium phosphate, and
phosphoric acid. A. Fischer did not obtain a deposit by the electrolysis of a
soln. of potassium cyanoplatinate.
The electrodeposition of platinum on metals has been effected by W. H. Wahl
by means of a bath of alkali platinate—a soln. of hydrated platinum dioxide in
alkali lye. R. Bottger, J. Wiess, and W. Rathenau employed a bath of alkali
chloroplatinate—a soln. of potassium chloroplatinate in alkali lye. M. Roseleur
and M. Lanaux, R. Bottger, W. A. Thorns, S. P. Thompson, M. Baum, K. Sadakata,
T. Yoshida, and the Platinum Plating Co. used a bath of alkali phosphatoplatinate
—say G. Nikolaus' recipe : where the electrolyte is a boiling soln. of 4 grms. of
platinic chloride, 2O grms. of ammonium phosphate ; 90 grms. of sodium phosphate ;
and 5 grms. of sodium chloride per litre. The article to be plated should be kept
in motion, and a potential difference of 6 to 8 volts employed. P. Jewreinoff, and
W. H. Wahl employed a bath of alkali oxalatoplatinate ; T. WiIm, F. Glaser,
A. Fischer, and H. Freudenberg employed a bath containing cyanide soln. ; and
R. Bottger, and W. C. Arzen, a soln. of ammonium chloroplatinate and sodium
citrate. The subject was discussed by M. Baum, R. Bottger, A. Church, D. Clerk
and C. A. Fawsitt, J. B. A. Dode, H. Elkington, L. l'Hote, T. Howse, J. H. Johnson,
H. H. Lake, W. A. Lampadius, H. H. Landois, S. T. Leo and T. N. Shen, L. B. G. de
Morveau, R. Namais, A. Polain, A. E. W. Smith, C. Stahlschmidt, L. M. Stoffel,
J. B. Thompson, A. Wogrinz, and J. Langness. M. de Kay Thompson, and
C. W. Keitel recommended a mixture of the cis- and trans-forms of platinum
dinitritodiamminonitrite obtained by treating a soln. of sodium chloroplatinate
with sodium nitrite, boiling, adding a slight excess of ammonia, and dissolving the
precipitate, after filtering and washing, in more ammonia. The bath is made up
by dissolving 1OO grms. of ammonium nitrate or sulphate in a litre of distilled water
containing 5 per cent, of ammonia, adding 2O grms. of the solid plating salt, and
heating. It is worked at 95° and is quite stable. It is kept ammoniacal, and
more salt is added as is necessary. H. S. Booth and M. Merlub-Sobel deposited
platinum from soln. of salts in liquid ammonia. R. H. Atkinson studied the
electrolytic transfer of the metal using fused chlorides as electrolytes ; G. G rube
and co-workers discussed the subject. In the electrolysis of soln. of platinum
chloride containing cerous chloride, A. B. Schiotz found that platinum alone is
deposited. M. Prasad and N. B. Choksey studied the effect of a magnetic field.
C. Sandonnini and V. N. Borghello observed no action occurred on electrolyzing
carbon tetrachloride with IO per cent, sulphuric acid and a platinum anode, but
with a lead anode dehalogenization occurred.
J. Plticker 18 noted the spluttering of platinum from the cathode in a discharge