Synthesis of MSn(OH)₆ by the Coprecipitation and Its Thermal Decomposition

Abstract

MSn(OH)₆ (M=Ca, Mg, Co, Cd, Zn) was synthesized by the coprecipitation method from dilute Na₂Sn(OH)₆ and M²⁺ solution, and characteristic properties of the precipitate were studied by X-ray diffractometry, thermogravimetry and differential thermal analysis. A linear relation between lattice constant ao and ionic radius of M²⁺ was found. By using mixed solution of Cd²⁺ and Mg²⁺, (Cd_1-x Mgx)Sn(OH)₆ was obtained. They decomposed to MSnO₃ by releasing water at the elevated temperature, which depended on M2+. The decomposition product of the first step was amorphous and upon the heating up to 600°C the amorphous phase transformed to crystalline.