Thermal behavior of some compounds of methanesulfonic acid with transition metals

Abstract

The following compounds of methanesulfonic acid, CH 3SO 3H, have been prepared: Cu(CH 3SO 3) 2 · 4 H 2O; Zn(CH 3SO 3) 2 · 4 H 2O; Mn(CH 3SO 3) 2 · 2 H 2O; Cd(CH 3SO 3) 2 · 2 H 2O and Ag(CH 3SO 3). Their thermal behavior has been studied using TG and DTA, together with X-ray analysis of the solid products formed during the heating. The water of hydration is evolved in one step (Mn, Cd) or in two step (Cu, Zn). The intermediate hydrates and the anhydrous salts are crystallized. The anhydrous Zn, Ag and Cd compounds melt, the anhydrous Cd salt undergoing a polymorphic transition before melting. They then begin to decompose in the temperature range 325–440°C. Under an inert atmosphere, the decomposition yields well-crystallized residues of various composition: Cu + Cu 2S; Ag + Ag 2S (the sulfides being in very minute amounts); MnS; CdS; ZnO + ZnS.