Synthesis and crystal structure of [Co(NH3)6][AuX4]X2 (X = Cl−, Br−)

Abstract

[Co(NH3)6][AuX4]X2 binary complex salts, where X = Cl− (I) and Br− (II), have been obtained and defined by element, X-ray diffraction, and thermal analyses and by IR, Raman, and electron spectroscopy. The compounds are isostructural. Their structural units are the [Co(NH3)6]3+ complex cations, the [AuX4]− complex anions, and the X− anions. The plane square environment of the gold atom is completed to an elongated bipyramid by two halide ions lying at distances Au...Cl 3.245 A for I and Au...Br 3.362 A for II. The thermolysis products of I and II are pure gold and cobalt metal powders when thermolysis is performed under hydrogen and a mixture of metallic gold with cobalt halide in a reaction under an inert atmosphere.