title: Syntheses and characterizations of compounds Ba4F4XGa2S6 (X = Cr, Mn, Fe) and Ba4F4MnIn2S6 with 2D layered structures.
abstract: Four new 2D layered quinary sulfides, Ba4F4CrGa2S6 (1), Ba4F4MnGa2S6 (2), Ba4F4FeGa2S6 (3) and Ba4F4MnIn2S6 (4), have been synthesized by the traditional solid state reaction method. Single crystal X-ray diffraction analyses show that the isostructural complexes 1, 3 and 4 belong to the Ba2F2Fe1.5S3 structure type and crystallize in the space group Pnma of the orthorhombic system, whereas the complex 2 crystallizes in the space group Cmca. The crystal structures of the four compounds can be viewed as the alternated stacking of the fluorite type [Ba2F2](2+) blocks and the newly discovered [X0.5GaS3](2-) or [X0.5InS3](2-) blocks. First-principles electronic structure calculations performed with DFT indicate that the title compounds are semiconductors with the band gaps of 1.83, 3.21, 1.16 and 2.93 eV for 1, 2, 3 and 4, respectively.
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, PR China.
authors.forename: Zhong-Zhen
authors.initials: ZZ
authors.lastname: Luo
authors.forename: Chen-Sheng
authors.initials: CS
authors.lastname: Lin
authors.forename: Wen-Dan
authors.initials: WD
authors.lastname: Cheng
authors.forename: Yuan-Bing
authors.initials: YB
authors.lastname: Li
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
authors.forename: Wei-Long
authors.initials: WL
authors.lastname: Zhang
authors.forename: Zhang-Zhen
authors.initials: ZZ
authors.lastname: He