title: Effect of halogen (Cl, Br) on the symmetry of flexible perovskite-related framework.
abstract: The perovskite structure is a good candidate for the design of functional materials. On the basis of the combination of B6O13 groups and XM6 (X = Cl, Br; M = alkali metals) octahedra, three new perovskite-related crystals Na3B6O10Cl, RbNa2B6O10Cl, and RbNa2B6O10Br have been synthesized by a high-temperature solution method for the first time. Na3B6O10Cl and RbNa2B6O10Cl are isostructural and crystallize in the noncentrosymmetric (NCS) space group P212121 (No. 19), while RbNa2B6O10Br belongs to the centrosymmetric (CS) space group Pnma (No. 62). The phenomenon that Cl-containing borates are not isostructural with corresponding Br-containing borates is extremely rare among borates. Detailed structure analysis suggests that the difference is owing to the effect of the halogen (Cl, Br) on the symmetry of the flexible perovskite-related framework. In addition, thermal analyses, IR spectroscopy, the UV-vis-NIR diffuse reflectance spectrum, and first-principles theoretical studies have also been performed on the three compounds.
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.
authors.forename: Chunyan
authors.initials: C
authors.lastname: Bai
authors.forename: Hongwei
authors.initials: H
authors.lastname: Yu
authors.forename: Shujuan
authors.initials: S
authors.lastname: Han
authors.forename: Shilie
authors.initials: S
authors.lastname: Pan
authors.forename: Bingbing
authors.initials: B
authors.lastname: Zhang
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.forename: Hongping
authors.initials: H
authors.lastname: Wu
authors.forename: Zhihua
authors.initials: Z
authors.lastname: Yang