Synthesis, crystal structure, infrared and Raman spectra of Sr{sub 5}(As{sub 2}O{sub 7}){sub 2}(AsO{sub 3}OH)

• Published in: Journal of solid state chemistry Vol. 177; no. 11
• Main Authors: Mihajlovic, T., Libowitzky, E., Effenberger, H.
• Format: Journal Article
• Language: English
• Published: United States 01-11-2004
• Subjects: ARSENIC OXIDES; BOND LENGTHS; CHEMICAL BONDS; HYDROTHERMAL SYNTHESIS; INFRARED SPECTRA; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; MONOCLINIC LATTICES; MONOCRYSTALS; RAMAN SPECTRA; SPACE GROUPS; STRONTIUM OXIDES; X-RAY DIFFRACTION
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2004.06.036

The new compound Sr{sub 5}(As{sub 2}O{sub 7}){sub 2}(AsO{sub 3}OH) was synthesized under hydrothermal conditions. It represents a previously unknown structure type and belongs to a group of a few compounds in the system SrO-As{sub 2}O{sub 5}-H{sub 2}O; (As{sub 2}O{sub 7}){sup 4-} besides (AsO{sub 3}OH){sup 2-} groups have not been described yet. The crystal structure of Sr{sub 5}(As{sub 2}O{sub 7}){sub 2}(AsO{sub 3}OH) was determined by single-crystal X-ray diffraction (space group P2{sub 1}/n, a=7.146(1), b=7.142(1), c=32.750(1)A, {beta}=93.67(3){sup o}, V=1668.0(5)A3, Z=4). One of the five symmetrically unique Sr atoms is in a trigonal antiprismatic (Inorg. Chem. 35 (1996) 4708)-coordination, whereas the other Sr atoms adopt the commonly observed ('Collect' data collection software, Delft, The Netherlands, 1999; Methods Enzymol. 276 (1997) 307)-coordination. The position of the hydrogen atom was located in a difference Fourier map and subsequently refined with an isotropic displacement parameter. Worth mentioning is the very short hydrogen bond length O{sub h}-H...O(1) of 2.494(4)A; it belongs to the shortest known examples where the donor and acceptor atoms are crystallographically different. This hydrogen bond was confirmed by IR spectroscopy. In addition, Raman spectra were collected in order to study the arsenate groups.