Arsenides


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Arsenides

 

compounds of arsenic with metals. They are solids and melt, as a rule, at high temperatures. They can be divided into two groups according to their composition and properties: derivatives of arseniuretted hydrogen (arsine), AsH3, which are decomposed by water and acids (arsenides of alkaline, alkaline earth, and several other metals—for example, K3As, Na3As, Ca3 As2, and Zn3As2); and intermetallic compounds, which are acid-resistant (for example, FeAs2, MnAs, Fe3 As2, and Ni5 As2). Arsenides are obtained by the reaction of elements, precipitation from solutions of metallic salts by arseniuretted hydrogen, and the reduction of arsenates. Several arsenides have semiconducting properties. The arsenides of the metals of Group III of the Mendeleev periodic system have acquired special significance; they crystallize in the structure of sphalerite (zincblende). Laser crystals (GaAs, InAs, Gajn, _ xAs), rectifiers, and tonal diodes and triodes (GaAs) are made from these arsenides.

Upon hydrometallurgical processing of several ores containing arsenides, the highly poisonous arseniuretted hydrogen (arsine) is released.

B. A. POPOVKIN

References in periodicals archive ?
On many dumps the pieces of ore have an earthy pink color (Vein 52, Ait Ahmane), as the cobalt arsenides and sulfarsenides (skutterudite, etc.
In the Aghbar deposit, at least two separate oxidation episodes affected the primary cobalt and nickel arsenides, creating a rich suite of secondary arsenates.
Well crystallized silver is found most frequently in narrow fissures in rhyolite, with arsenides (safflorite, lollingite) or sulfides (chalcopyrite).
2] * (2) Gold Au ** (2) Iridium (Ir,Os) * (5) Osmium (Os,Ir) * (5) Sulfur S *** Silver Ag (m) (2) Sulfides, Arsenides, Telluride Acanthite [Ag.
Since the early 1930's there have been numerous publications about the Bou Azzer mining district--chiefly geological and economic studies concerning extraction of cobalt and nickel arsenide ores.
Currently the workings exploit primary arsenide ores.
A general rule for the Bou Azzer district is that all Co-Ni-Fe arsenide ore mineralization occurs at contacts with serpentinite.
As Leblanc (1980) has suggested, it seems clear that the "Bou Azzer" type of deposit can be defined as: "Cobalt arsenide deposits in serpentinite with overlying silicate-carbonate sedimentary rocks, the ore concentration resulting from tectonic remobilization and surficial weathering.