Exploring new belousovite-related zinc and cadmium alkali sulfate halides: synthesis and structural variability.

Fourteen new belousovite-related compounds, AZn(TO 4 )X (A = K, Rb, Cs, Tl, NH 4 ; T = S, Se; X = Cl, Br, I) have been prepared via melt and evaporation techniques by reacting AX and ZnTO 4 either at high temperatures or in hot aqueous solutions. They adopt the layered structure of the belousovite archetype, and constitute a morphotropic series. The apophyllite-type layers in these structures undergo different corrugations, most pronounced in the case of CsZn(SO 4 )I. In addition, during the study two species unrelated to belousovite, namely Na 4 Zn(SO 4 ) 2 Cl 2 and Cs 2 Cd 3 (SO 4 ) 4 , were found with framework crystal structures having different topology and belonging to new structure types.