Towards new cesium containing manganese vanadates via a precursor method

Abstract

Two new cesium containing manganese vanadates are synthesized by a facile method. The known compound K₂Mn(VO₃)₄ (1), synthesized via a milder method than the previous hydrothermal reaction, was firstly used as a precursor to prepare two new manganese vanadates, namely CsMn(VO₃)₃·H₂O (2) and Cs_4.34Mn_1.83(VO₃)₈·2.965H₂O (3) in concentrated Cs⁺ aqueous solutions at 80 °C. Compound 2 features a three-dimensional (3D) microporous framework constructed from serrated (VO₃)_n chains interconnected by Mn²⁺ ions. The Cs⁺ ions and the lattice water molecules are located in the channels of the structure along the a-axis. In compound 3, the sinusoidal (VO₃)_n chains are linked by Mn²⁺ ions into V–O–Mn double chains, which are further weaved by {Mn₄O₈} units to form a 3D microporous network with channels occupied by disordered Cs⁺ ions. Compounds 2 and 3 are the first Cs–Mn–V–O examples with a 3D microporous framework. Thermal stabilities of compounds 2 and 3 were investigated by thermogravimetric (TG) analysis. This work provides an effective synthetic method for preparing alkali-metal containing heterometallic vanadates with new composition and structures.