title: Pb6Ba2(BO3)5X (X = Cl, Br): new borate halides with strong predicted optical anisotropies derived from Pb(2+) and (BO3)(3.).
abstract: Two new borate halides, Pb6Ba2(BO3)5X (X = Cl, Br), have been synthesized by solid-state reactions and their structures determined by single-crystal X-ray diffraction. They are isostructural and feature 3D frameworks composed of alternate stacking of [PbBO] and [PbBOX] layers which are connected by 10-coordinated Ba atoms along the c direction. First-principles calculations show that both compounds have a large birefringence of 0.1582 and 0.1810 at 532 nm, respectively. The large birefringence originates from the strong optical anisotropies of the Pb(2+) cations and (BO3)(3-) groups based on the real-space atom-cutting analysis. The IR and UV-Vis-NIR diffuse reflectance spectroscopy, as well as thermal stability analyses of both compounds, were performed.
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. ffzhang@ms.xjb.ac.cn slpan@ms.xjb.ac.cn.
authors.forename: Lu
authors.initials: L
authors.lastname: Liu
authors.forename: Bingbing
authors.initials: B
authors.lastname: Zhang
authors.forename: Fangfang
authors.initials: F
authors.lastname: Zhang
authors.forename: Shilie
authors.initials: S
authors.lastname: Pan
authors.forename: Fangyuan
authors.initials: F
authors.lastname: Zhang
authors.forename: Xingwen
authors.initials: X
authors.lastname: Zhang
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Dong
authors.forename: Zhihua
authors.initials: Z
authors.lastname: Yang