Thermal decomposition of metal complexes—VI some ammine cobalt (II) complexes

Abstract

The thermal dissociation of a number of cobalt (II) ammine complexes of the type, [Co(NH 3) 6]X 2 (X = Cl, Br, I, and NO 3), and [Co(NH 3) 6]SO 4, were studied by thermogravimetry, differential thermal analysis, and gas evolution analysis. The thermal dissociation of these complexes involved intermediate ammine complexes containing lower ammonia to cobalt ratios. For the chloride and bromide complexes, the dissociation sequence was: [Co(NH 3) 6]X 2 → [Co(NH 3) 2]X 2 → [Co(NH 3)]X 2 → CoX 2. The stoichiometry of the dissociation of [Co(NH 3) 6](NO 3) 2 was: 9[Co(NH 3) 6 (NO 3) 2 → 3Co 3O 4 + 30NH 3 + 36H 2O + 17N 2 + 4NO + 2N 2O.