title: Effect of the cation size on the framework structures of magnesium tungstate, A4Mg(WO4)3 (A = Na, K), R2Mg2(WO4)3 (R = Rb, Cs).
abstract: A series of alkali metal magnesium tungstates, A4Mg(WO4)3 (A = Na, K), R2Mg2(WO4)3 (R = Rb, Cs), were synthesized from a high temperature solution, and their structures were determined by single-crystal X-ray diffraction. Interestingly, Na4Mg(WO4)3 crystallizes in the monoclinic space group C2/c, while K4Mg(WO4)3 having an identical stoichiometry with Na4Mg(WO4)3, exhibits a different framework structure belonging to triclinic symmetry with the space group P1[combining macron]. Isostructural Rb2Mg2(WO4)3 and Cs2Mg2(WO4)3 crystallize in the space group P213 of cubic symmetry and reveal a three dimensional framework composed of isolated WO4 tetrahedra, MgO6 octahedra and RO12 (R = Rb, Cs) polyhedra. The effect of the alkali metal cation size on the framework structures of magnesium tungstate has been discussed in detail. In addition, the infrared spectra, as well as the UV-Vis-NIR diffuse reflectance spectroscopy data, are reported. The first-principles theoretical studies are also carried out to aid the understanding of electronic structures and linear optical properties.
authors.affiliation: Key Laboratory of Functional Materials and Devices for Special Environments of CAS; Xinjiang Key Laboratory of Electronic Information Materials and Devices; Xinjiang Technical Institute of Physics & Chemistry of CAS, 40-1 South Beijing Road, Urumqi 830011, China. slpan@ms.xjb.ac.cn zhyang@ms.xjb.ac.cn.
authors.forename: Shujuan
authors.initials: S
authors.lastname: Han
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.forename: Qun
authors.initials: Q
authors.lastname: Jing
authors.forename: Hongping
authors.initials: H
authors.lastname: Wu
authors.forename: Shilie
authors.initials: S
authors.lastname: Pan
authors.forename: Zhihua
authors.initials: Z
authors.lastname: Yang