Gmelin's Handbuch der anorganischen Chemie

Abstract

THE parts of “Gmelin's Handbuch” under notice deal with osmium and platinum. Osmium, the heaviest of all known substances, has a high melting point and is harder than glass and quartz but is scratched by topaz. Its scarcity and its tendency to form the highly poisonous, volatile, strongly smelling tetroxide prevents its commercial exploitation. It is a highly efficient catalyst, especially in hydrogenations. The tetroxide dissolves in water to give a neutral solution with an extremely small electrical conductance ratio, but it forms salts with bases. It is readily reduced to lower oxides or to the metallic state. Thus in alkaline solution its valency falls to 6, and in neutral and acid solution to 4, the dihydrate of osmium dioxide being formed; but reoxidation by oxygen is readily affected so that it is an excellent oxygen carrier. With concentrated hydrochloric acid it gives chlorine. On heating the metal in chlorine a series of intensely coloured sublimates is formed. These are difficult to separate, but at 650° C. a black tetrachloride can be obtained.

Gmelin's Handbuch der anorganischen Chemie

Achte völlig neu bearbeitete Auflage. Herausgegeben von der Deutschen Chemischen Gesellschaft. System-Nummer 66: Osmium, mit einem Anhang über Ekaosmium. Pp. xx + iv+ 100. 14.25 gold marks. System-Nummer 68: Platin. Teil A, Lief. 1: Geschichtliches Vorkommen. Pp. 146. 16.50 gold marks. Teil B, Lief. 1: Physikalische Eigenschaften des Metalls (bis thermische Eigen-schaften). Pp. 72 + iv. 8.25 gold marks. (Berlin: Verlag Chemie, G.m.b.H., 1938–39.)