RbLiZn5(PO4)4 and BaLiZn3(PO4)3: two new zinc orthophosphates with all tetrahedra-based anion frameworks

Abstract

Inorganic functional materials based on phosphates have attracted heavy attention due to diverse structures and ravishing properties. Two new zinc orthophosphates, RbLiZn5(PO4)4 and BaLiZn3(PO4)3, have been obtained through hydrothermal and high temperature solid reaction respectively. RbLiZn5(PO4)4, which is the first rubidium lithium zinc phosphate, crystallizes in a monoclinic space group of C2/c featuring a three-dimensional (3D) [LiZn5(PO4)4]– anion framework composed of parallel 2D [(Zn2(PO4)2]∞ slab and [ZnLi(PO4)4]∞ chains, which are formed by the ZnO4 and LiO4 groups connected with isolated PO4 groups. BaLiZn3(PO4)3, which is the first barium lithium zinc phosphate, crystallizes in an orthorhombic space group of Pccn with the 3D [(LiZn)Zn2PO7]4– anion skeleton created by two mirror-symmetric zigzag [Zn(ZnLi)O7]∞ chains connected with isolated PO4 groups through corner-sharing. The Rb+ and Ba2+ are located in the empty space of the structure as the counter cations. Besides crystal structures analysis, thermal stability and optical properties measurements as well as theoretical studies of the title phosphates were conducted.