Gold phosphides

Copper, Silver and Gold Phosphides.—The copper phosphides are crystalline compounds of metallic appearance and properties which are usually prepared by direct union of the elements.8 Phosphorus begins to combine with copper at about 400° C., and at 700° C. the copper was found to take up 20 per cent.,9 some of which was expelled at higher temperatures. Slightly above the melting-point of the phosphide 14 per cent, was retained, which corresponds to tri-cuprous phosphide, Cu3P.9 The velocity of the combination increases between 600° and 700° C.10 At ordinary pressures 15 per cent, of phosphorus is the limit of the amount which will remain dissolved in the fused mixture, and some of this is present as red phosphorus.11... 

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. 

Gold phosphides.—Gold sesquiphosphide, AUgPg, is said to be formed by heating phosphorus with gold.8... 

Gold forms no simple phosphide Au2P3 is AuJ(Pg ) with P—Au—P angles of 171 and 180°. 

It reduces copper, silver and gold salts in solutions, precipitating metal phosphides or the metals themselves ... 

Figure 1.32 Oligomeric gold(l) complexes with phosphide or phosphine ligands.

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... 

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 —... 

Red phosphorus is less soluble than white in all solvents. In water and alcohol it is almost insoluble. It is somewhat soluble in ether and in hot acetic acid, from which it is reprecipitated by water. It is slightly soluble in phosphorus trichloride. These solubilities refer to the ordinary preparation, which, as shown on p. 32, usually contains residual quantities of the white form. Red phosphorus is able to reduce salts, especially those of the noble metals, in aqueous solution on boiling. Salts of mercury are reduced to the metal those of gold and silver give insoluble phosphides while ferric and stannic salts are reduced to ferrous and stannous respectively.5... 

Gold, like silver, when in the molten state dissolves phosphorus and rejects it on solidification.18 A phosphide AuP has been prepared by passing a mixture of dry phosphine and ether vapour into an ether solution, of gold chloride.19 The phosphorus is only loosely combined and is given off when the compound is warmed. Such phosphides... 

Compounds of Gold and Phosphorus.—Phosphine reacts with a solution of auric chloride in anhydrous ether, forming auric phosphide, AuP, a substance decomposed by water or potassium-hydroxide solution, with formation of phosphine and phosphoric add.2 At 100° to 110° C. it-undergoes oxidation in the air. Heating in a current of carbon dioxide causes volatilization of phosphorus. Nitric acid oxidizes the phosphorus, leaving a residue of metallic gold. These reactions indicate the substance to be an alloy of gold and phosphorus. 

Another phosphide, Au3P4, is produced by the interaction of phosphorus vapour and gold.3 It is a grey, brittle substance, of density 6-67, and is formed only in the neighbourhood of 400° C.4 Acids react with it as with an alloy. 

Good examples of cyclic (mostly polycyclic) structures are provided by metal alkoxides. Some spectacular rings are the gold (I)-phosphide complexes of the type [AuPR2] (n = 3, 4 or 6). ... 

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