(NH4)(Zn,Ga)2(PO4)2, an open-framework structure

Abstract

Ammonium di­(zinc, gallium) bis­(phosphate), (NH4)(Zn,Ga)2(PO4)2, has a zeolite-like open-framework structure. It contains channels of four- and eight-membered rings of alternating tetrahedra of (Zn,Ga)O4 (Zn:Ga ≃ 1:1) and PO4, in which the tetrahedra are connected via corners. The NH4+ cations are located in the channels and provide weak hydrogen bonds to the framework O atoms. The average (Zn,Ga)—O bond lengths of the two non-equivalent (Zn,Ga)O4 tetrahedra are 1.863 and 1.870 Å. All atoms are in general positions. The compound is isostructural with K(CoII,Al)2(PO4)2 and [(NH4)x(NH3)0.5−x]CoxAl1−xPO4 (x = 0.38). Single-crystal Raman and IR spectra are discussed.