Platinum phosphides

P. Burckhard found that the electrolysisof tetrasodium pyrophosphate is attended by the evolution of much oxygen at the anode, and at the platinum cathode, gas bubbles are formed which inflame spontaneously in air, and platinum phosphide is formed. P. Walden found the eq. electrical conductivity of aq. soln. of tetrasodium pyrophosphate at 25° for soln. with one gram of the salt in v litres of water ... 

Methods of Preparation—Alkali Phosphides—Alkaline Earth Phosphides— Copper, Silver and Gold Phosphides—Zino Group Phosphides—Boron and Aluminium Phosphides—Titanium Group Phosphides—Tin and Lead Phosphides—Arsenic, Antimony and Bismuth Phosphides—Chromium, Molybdenum and Tungsten Phosphides—Manganese Phosphides—Iron, Cobalt and Niokel Phosphides—Platinum Phosphides. 

According to SAXS data, the molecules of platinum phosphide complex [(PPh2)Pt]g io are almost spherical in shape with a mean diameter of 15.2 A. Unlike the platinum analog, treatment of the palladium complex [ (Ph3 P)Pd(OAc)2]2... 

Table 4.1). In the mass spectmm of 38, the organyl-free fragment [PtPJ" was observed, and hence this complex may be a suitable molecular precursor for the synthesis of binary phosphorus-rich platinum phosphides. 

Iseler, G. W. et al., Int. Conf. Indium Phosphide Relat. Mater., 1992, 266 Reaction of beryllium, copper, manganese, thorium or zirconium is incandescent when heated with phosphorus [1] and that of cerium, lanthanum, neodymium and praseodymium is violent above 400°C [2], Osmium incandesces in phosphorus vapour, and platinum bums vividly below red-heat [3], Red phosphorus shows very variable vapour pressure between batches (not surprising, it is an indeterminate material). This leads to explosions when preparing indium phosphide by reactions involving fusion with phosphorus in a sealed tube [4],... 

Bertrand Pelletier, 1761-1797. French chemist and pharmacist who investigated the arsenates, phosphates, and phosphides of many metals, studied the action of phosphorus on platinum, and devised new methods for making soap and refining metal for clocks. He served as inspector of the hospitals m Belgium. His son, Joseph Pelletier (1788-1842), and Joseph Caventou discovered quinine, cmehomne, strychnine, and brucine. See also ref. (89). 

Which is the best catalyst for accelerating the reaction depends on the nature of the working materials. For the reaction of hydrogen or oxygen in potassium hydroxide solution, nickel or silver is suitable for carbonaceous fuels as well as for the reaction of oxygen in acid electrolytes platinum metals were up to the middle 60s, the only known catalysts. Precious metals are ruled out by price for wide application in fuel cells, and the search for cheaper catalysts has been actively pursued in many research laboratories. Many classes of inorganic substances (carbides, nitrides, oxides, sulfides, phosphides, etc.) have been investigated and, in particular, several chelates. 

Phosphorus unites with most of the metals, forming phosphides. Phosphorus is electronegative towards hydrogen, and its affinity for the metals is rather less than that of sulphur. The phosphides are made by the direct union of the two elements usually assisted by heat, and in an atmosphere of an inert gas to prevent undue oxidation. In this way, at a dull red-heat, the metals iron, nickel, cobalt, copper, manganese, palladium, platinum, and iridium united with phosphorus with incandescence and gold, silver, tin, and zinc without incandescence. Phosphides VOL. VIII. 3 B... 

Sulphur alone has no action upon platinum,3 but metallic sulphides are liable to attack it. Phosphorus, phosphides, and phosphates under reducing conditions attack the metal, so that these and the aforesaid sulpirides should not be ignited in platinum crucibles in quantitative analysis. Ferric chloride solution is reduced to ferrous chloride when evaporated in a platinum dish, platinum passing into solution. 

Platinum Monophosphide, PtP, was presumably obtained by Pelletier in 1792 3 as the result of heating platinum and phosphorus tog-ther until the metal had absorbed 18 per cent, of the phosphorus. The same phosphide is also obtained by boiling the complex Pt3P5, mentioned above, with aqua regia for many hours, whereby a residue of monophosphide is obtained, the diphosphide passing into solution.1... 

The metal may be deposited on a piece of platinum, gold or carbon at some distance from the stick of phosphorus with which this is in contact. The silver phosphide which was first produced had the formula AgsP and phosphorous acid was formed simultaneously. The following equations were suggested as representing the various stages —... 

A complex acid is probably present when silica dissolves in phosphoric acid, as it does to the extent of about 5 per cent, at 260° C.6 Concentrated phosphoric acid at 100° to 200° C. etches the surface of glass, and it has been found to attack quartz at 300° C.7 Phosphoric acid at high temperatures also destroys the glaze on porcelain. Platinum is not affected unless a reducing agent is present, which may give phosphorus and a phosphide. 

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