Wu, Y. D. and Bensch, W. (2011) K(3)BiAs(6)Se(12): A two-dimensional bismuth selenoarsenate containing crown-shaped anions As(3)Se(6) (3-). Journal of Alloys and Compounds, 509 (13). pp. 4452-4456. DOI 10.1016/j.jallcom.2011.01.108.

Abstract

Single crystals of K(3)BiAs(6)Se(12) were obtained from the reaction of Si, with in situ formed fluxes of K(2)Se(3), As(2)Se(3), and Se at 500 degrees C. The compound crystallizes in the trigonal space group P (3) over bar (No. 147) with a = 9.7478(7), c = 7.6525(6)angstrom, V = 629.72(8)angstrom(3), Z=1. The Bi(As(3)Se(6))(2)(3-) anion possesses a two-dimensional layered structure with trigonal symmetry consisting of BiSe(6) octahedra and crown-like cyclic As(3)Se(6)(3-) units formed by three corner-sharing trigonal pyramidal AsSe(3)(3-) anions. The As(3)Se(6)(3-) fragment is located on a 3-fold axis with three As atoms and three Se atoms forming a six-membered ring in chair conformation. The Bi(3+) ion is in an almost perfect octahedral geometry. The overall arrangement of the Bi(3+) cations and the As(3)Se(6)(3-) anions is related to the CdI(2)-type structure with the cations situated on the Cd(2+) and the anions on the I(-) sites, respectively. The K(+) cations are located between the Bi(As(3)Se(6))(2)(3-) layers. The K(1)(+) cation is coordinated by 9 Se(2-) anions from four As(3)Se(6)(3-) units, one above and three below, in an irregular geometry, whereas the K(2)(+) cation is surrounded by six Se(2-) anions from four As(3)Se(6)(3-) units, two above and two below, in a perfect octahedral fashion. The title compound is characterized with UV/vis diffuse reflectance spectroscopy, IR and Raman spectra. (c) 2011 Elsevier B.V. All rights reserved.

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