title: Five new chalcohalides, Ba3GaS4X (X = Cl, Br), Ba3MSe4Cl (M = Ga, In), and Ba7In2Se6F8: syntheses, crystal structures, and optical properties.
abstract: Five new chalcohalides, Ba3GaS4X (X = Cl, Br), Ba3MSe4Cl (M = Ga, In), and Ba7In2Se6F8, have been synthesized by conventional high-temperature solid-state method. These compounds crystallize in three different interesting structure types. Ba3GaQ4X (Q = S, X = Cl, Br; Q = Se, X = Cl) contain zigzag BaX pseudolayers and isolated GaQ4 tetrahedra, while Ba3InSe4Cl possesses one Ba-In-Se pseudolayer and one Ba-Cl pseudolayer, which are stacked alternately along the c-direction. Ba7In2Se6F8 is comprised of one-dimensional 1∞[InSe3]3- chains and unique [Ba7F8]6+ chains. In all those mixed anion compounds, the halide anions are only connected to alkaline-earth metal through strong ionic bonding, while the M (M = Ga, In) cations are only connected to chalcogenide anions through covalent bonding. UV-vis-NIR spectroscopy measurements indicate that Ba3GaQ4X (Q = S, X = Cl, Br; Q = Se, X = Cl) have band gaps of 2.14, 1.80, and 2.05 eV, respectively.
authors.affiliation: Center for Crystal Research and Development and ‡Key Laboratory of Functional Crystals and Laser Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing 100190, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Feng
authors.forename: Wenlong
authors.initials: W
authors.lastname: Yin
authors.forename: Zuohong
authors.initials: Z
authors.lastname: Lin
authors.forename: Jiyong
authors.initials: J
authors.lastname: Yao
authors.forename: Yicheng
authors.initials: Y
authors.lastname: Wu