A Comprehensive Treatise on Inorganic and Theoretical Chemistry

PLATINUM 161
num. at 200°. O. J. Walker observed that in the precipitation of copper or silver
from soln. of their salts by phosphorus, if a conducting metal like platinum be in
contact with the phosphorus, the silver or copper is deposited on the platinum.
H. Moissan observed that when phosphorus trifluoride or pentafluoride is passed
over red-hot spongy platinum, some platinous phosphopentafluoride, PtF2.PF3,
and phosphide are formed. EJ. Baudrimont found that spongy platinum and
phosphorus trichloride at 250° form a platinum chloride ; J. H. Gladstone said
that the compact metal is not attacked. W. R. Hodgkinson and F. K. S. Lowndes
found that a red-hot platinum wire in the vapour of phosphorus pentachloride
produces a flame, some phosphorus is formed, and this reacts with the metal,
forming a fusible phosphide. According to E. Baudrimont, phosphorus pentachloride,
at 200°, attacks the metal, and at a higher temp., a volatile compound
of platinic and phosphoric chlorides is formed. The subject was also studied by
P. Sehtttzenberger, and P. Schiitzenberger and M. Fontaine. H. Goldsehmidt
TABLE III.—THE EFFECT or PHOSPHORUS O.N THE TENACITY OF PLATINUM.
r
per cent.
0-26
0-105
0-025
0-005
0-003
0-001
O-0OO
Yield
21-4
16-8
16-3
13-9
10-4
12-2
8-7
Ki >om temperatures
Fracture
2R-9
23-5
21-4
20-9
13-9
14-9
14-8
Elongation
4-75
11-3
19-4
11-9
14-2
24-9
271
Yield
— -
3-6
6-2
5-1
850°
Fracture
- -
4-2
7-9
6-9
TCluiigatioii
represented the reaction with compact platinum POl 5 +Pt ^-POl3+Pt Cl2-
W. Ramsay and J. Shields observed that no hydrogen is liberated by boiling
platinum black with a soln. of sodium hypophosphite owing to the oxygen occluded
by the metal. The reaction was studied by A. Sieverts, and M. Major. A. Sieverts
observed that platinum black is a catalyst for the oxidation of the hypophosphite.
A. A. Vedensky and A. V. Frost found that colloidal platinum favours the oxidation
of phosphorous acid. F. l^oessner studied the action of hypophosphorous acid.
R. E. Barnett noted that platinum pyrophosphate is formed when the metal is
heated with phosphorus pentoxide in oxygen. According to O. Huttner, a hot,
cone. soln. of phosphoric acid attacks platinum in air, but not if air be excluded.
C. W. Jurisch also noticed that molten phosphoric acid attacks platinum. B. Pelletier
observed that glacial phosphoric acid attacks platinum in the presence of carbon.
M. Schmoger found that platinum crucibles are not attacked at a red-heat by
magnesium pyrophosphate, but if reducing conditions are present, W. C. Heraeus
observed that the metal is disintegrated at 900°. The subject was discussed by
G. E. F. Lundell and J. 1. Hoffman.
A. F. Gehlen 18 observed that when spongy platinum is heated with arsenic,
the combination is attended by vivid incandescence ; L. Wohler prepared PtAs2 ;
and W. R. Hodgkinson and F. K. S. !Lowndes found that a red-hot platinum wire
is immediately fused when in contact with arsenic—vide 9. 51, 10. A. F. Gehlen
found that neither arsenic trioxide nor arsenic acid exerts any action on the
metal—vide 9. 51, IO. E. Mulder observed that platinum black transforms arsenic
trioxide in aq. soln. into arsenic pentoxide, and C. Engler and L. Wohler added that
this occurs in the absence of air owing to the absorbed oxygen. J. H. Gladstone
and A. Tribe observed the reduction of arsenious acid in aq. soln. to arsenic by
hydrogenized platinum. H. E. Patten observed that platinum is blackened by
arsenic trichloride ; and L. Kahlenberg and J. V. Steinle observed no reaction
VOL. XVI. M
6-2
61
OO