Studies on metal hydroxy compounds. I. Thermal analyses of zinc derivatives ϵ-Zn(OH) 2 , Zn 5 (OH) 8 Cl 2 .H 2 O, β-ZnOHCl, and ZnOHF

Abstract

Thermogravimetric (t.g.a.) and differential thermal analyses (d.t.a.) of ϵ-Zn(OH) 2 , Zn 5 (OH) 8 Cl 2 .H 2 O, β-ZnOHCl, and ZnOHF are reported and discussed. The results show that the replacement of a hydroxyl group by a halogen group contributes to greater thermal stability of the hydroxy compound. The thermal stability increases in the order ϵ-Zn(OH) 2 < Zn 5 (OH) 8 Cl 2 < β-ZnOHCl < ZnOHF.The hydroxy compounds decompose via dehydration in the initial step followed by hydrolysis of the zinc halide and (or) volatilization of the zinc halide yielding an ultimate residue of zinc oxide and trace quantities of the zinc halide.