Syntheses and structures of ammonium transition-metal dialuminium tris(phosphate) dihydrates (NH₄)MAl₄(PO₄)₃·2H₂O (M = Mn and Ni)

Abstract

The structures of ammonium manganese(II) dialuminium tris(phosphate) dihydrate, (NH4)MnAl2(PO4)3·2H2O, and ammonium nickel(II) dialuminium tris(phosphate) dihydrate, (NH4)NiAl2(PO4)3·2H2O, were determined using single-crystal diffraction data. The structures of title compounds are isotypic to cobalt aluminophosphate, (NH4)CoAl2(PO4)3·2H2O (LMU-3) [Panz et al. (1998). Inorg. Chim. Acta, 269, 73–82], in which a three-dimensional network of vertex-sharing AlO5 and PO4 moieties delineate twelve-membered channels in which ammonium, NH4 +, and transition-metal cations (M = Mn2+ and Ni2+) reside as charge compensators for the anionic [Al2(PO4)3]3– aluminophosphate framework. In both structures, the N atom of the ammonium cation, the transition-metal ion and one of the P atoms lie on crystallographic twofold axes.