Ruthenium arsenide

Ruthenium Arsenide, RuAs2, may be prepared in an exactly similar manner to rhodium arsenide. The method of analysis described under palladium arsenide (p. 73) may be applied to both of these arsenides. 

A few compounds of the platinum metals are met, but always in rare minerals. Sperrylite Is platinum arsenide, PtAs2, which is found in rare samples of the nickel-copper ores of Ontario and of copper ores at Rambler Mine, Laramie, Wyoming. Laurite is a rare ore composed mainly of ruthenium sulfide, RuS2. 

Ruthenium, osmium, rhodium, iridium, palladium and platinum are the six heaviest members of Group VII1. They are rare elements platinum itself is the commonest with an abundance of about 10-6% whereas the others have abundances of the order of 10"7 % of the earth s crust. They occur in Nature as metals, often as alloys such as osmiridium, and in arsenide, sulfide and other ores. The elements are usually associated not only with one another but also with the coinage metals copper, silver and gold. The main suppliers are South Africa, Canada and the USSR. 

W. D. Johnston, Jr., H. J. Leamy, B. A. Parkinson, A. Heller, and B. Miller, Effect of ruthenium ions on grain boundaries in gallium arsenide thin film photovoltaic devices, J. Electrochem. Soc. 127 (1980) 90-95. 

The development of a new generation of catalysts and semiconductors will be needed if a photochemical process (using solar radiation) is to be viable, but research and development in this area is growing rapidly. The sources of hydrogen include hydrocarbons, alcohols, and organic acids. Ruthenium, rhodium, and iridium catalysts, and various arsenide, selenide, and telluride semiconductors (see Chapter 15), may lead the way to an efficient system. 

---