The Crystal Structures and Raman Spectra of Three New Hydrothermally Synthesized Copper–Zinc–Oxotellurates(IV)
Missen, OP and Weil, M and Mills, SJ and Libowitzky, E and Kolitsch, U and Stoger, B, The Crystal Structures and Raman Spectra of Three New Hydrothermally Synthesized Copper-Zinc-Oxotellurates(IV), Journal of Inorganic and General Chemistry, 646, (11-12) pp. 476-488. ISSN 0044-2313 (2020) [Refereed Article]
Three new copper–zinc–tellurites, Zn4Cu(TeIVO3)4Cl2, Cu2Zn2(TeIVO3)2(SO4)(OH)2·H2O and Cu2Zn(TeIVO4)(SO4)·H2O (henceforth I, II and III), were synthesized under mild hydrothermal conditions (473 K, in Teflon-lined steel vessels). They were characterized in detail by a combination of crystal-structure determination (using single-crystal X-ray diffraction data), single-crystal micro-Raman spectroscopy and chemical analyses (energy-dispersive X-ray spectroscopy in a scanning electron microscope). Each compound crystallizes in a new structure type, and additionally, II and III represent the first two ever reported copper–zinc–tellurite–sulfates. I [systematic name: tetrazinc copper(II) tetrakis-oxotellurate(IV) dichloride] is triclinic, P1, and forms a framework structure based on ZnO6 and ZnO5Cl octahedra, linked into sheets connected via Jahn–Teller-distorted CuO4Cl2 octahedra, with TeIVO3 trigonal pyramids and TeIV2O6 dimers (composed of two edge-sharing TeIVO4 disphenoids) filling the remaining space. II [dicopper(II) dizinc bis-oxotellurate(IV) oxosulfate(VI) bis-hydroxide monohydrate] is trigonal, R3m, with a simonkolleite-like framework. Distinct layers formed from (Cu,Zn)φ6 (φ = O, OH) octahedra and TeIVO3 trigonal pyramids extend parallel to (001) and sandwich disordered SO42– anions and H2O groups. III [dicopper(II) zinc oxotellurate(IV) oxosulfate(VI) hydrate] is orthorhombic, Pnma, and also has a layered structure [extending parallel to (100)]. Positively charged layers of composition [Cu2ZnTeIVO4]2+ (containing Te as TeIVO4 disphenoids) alternate with SO42– anions and H2O groups in the interlayer space. Stacking disorder caused by the order-disorder nature of the crystal structure is reflected by the presence of residual electron density in difference-Fourier maps and the structure was refined as an overlay of two stacking possibilities.