Syntheses, crystal structures of a series of novel alkali metal or alkaline earth metal phosphites

Abstract

A series of new alkali metal and alkali-earth metal phosphites, namely, NaIn₃(HPO₃)₅(H₂O)₄, AIn(HPO₃)₂ (A = Rb, Cs) and Ba₃M₂(HPO₃)₆ (M = Al, Ga, In), have been synthesized by hydrothermal reactions. Their structures have been determined by single-crystal X-ray diffraction. The structure of NaIn₃(HPO₃)₅(H₂O)₄ shows a complicated 3D anionic framework based on InO₆ octahedra connected by HPO₃ tetrahedra via corner-sharing, and the 3D anionic network of NaIn₃(HPO₃)₅(H₂O)₄ can also be described as a new 3,5-net with a Schläfli symbol of {4.8²}{4².6.8⁷}{4².6}3{4².8⁸}{4³.6².8⁵}{8³}. Both AIn(HPO₃)₂ (A = Rb, Cs) feature a 2D layer composed by InO₆ octahedral and HPO₃ tetrahedral units with alkali metal cations filling the interlayer spaces. Ba₃M₂(HPO₃)₆ (M = Al, Ga, In) are isomorphous, and their structures feature a 3D anionic framework composed of MO₆ (M = Al, Ga, In) octahedra and HPO₃ tetrahedra interconnected via corner-sharing. IR and UV-vis spectra and TGA curves of these materials were also measured.