title: Ba3LnInS6 (Ln = Pr, Sm, Gd, Yb) and Ba2LnGaS5 (Ln = Pr, Nd): syntheses, structures, and magnetic and optical properties.
abstract: Six new quaternary rare-earth sulfides Ba(3)LnInS(6) (Ln = Pr, Sm, Gd, Yb) and Ba(2)LnGaS(5) (Ln = Pr, Nd) have been synthesized for the first time. Ba(3)LnInS(6) (Ln = Pr, Sm, Gd, Yb) belong to the centrosymmetric space group R3[overline]c of the trigonal system. The structures contain infinite one-dimensional anionic chains (1)(∞)[LnInS(6)](6-), which are built from face-sharing LnS(6) distorted triangular prisms and InS(6) octahedra. Ba(2)LnGaS(5) (Ln = Pr, Nd) crystallize in the centrosymmetric space group I4/mcm of the tetragonal system. Their structures consist of (BaLn)S layers built from (BaLn)S(8) bicapped trigonal prisms. These layers are stacked perpendicular to the c axis and further connected by GaS(4) tetrahedra to form a three-dimensional framework with channels occupied by Ba(2+) cations. As deduced from magnetic susceptibility measurements on Ba(2)NdGaS(5), it is paramagnetic and obeys the Curie-Weiss law. Besides, the band gap of Ba(2)NdGaS(5) is determined to be about 2.12(2) eV.
authors.affiliation: Center for Crystal Research and Development, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Feng
authors.forename: Youguo
authors.initials: Y
authors.lastname: Shi
authors.forename: Wenlong
authors.initials: W
authors.lastname: Yin
authors.forename: Wendong
authors.initials: W
authors.lastname: Wang
authors.forename: Jiyong
authors.initials: J
authors.lastname: Yao
authors.forename: Yicheng
authors.initials: Y
authors.lastname: Wu