| | 1 | Author
| Joachim Fuchs | Requires cookie* | | | Title
| Kristallstrukturen und Schwingungsspektren zweier  | | | | Abstract
| isomerer Oktadekawolframatodiarsenate, (NH4)6As2W180 62 • #iH20 C rystal S tructures and V ibrational Spectra of Tw o Isom ers of O ctadecatungsto-diarsenate (N H 4)6A s2W 18 0 6 2 • mH20 H o lg er N eu b e rt Six possible structures of A s2W ,80 626~ are discussed, and an exact nom enclature is proposed. The structures of the isomeric title compounds (I and II) were determ ined by X-ray diffraction. I crystallizes in space group P I with lattice param eters a = 12.965(4), b = 14.803(5), c = 18.515(6) Ä; a = 96.280(23)°, ß = 91.420(25)°, y — 115.320(25)°. The anion has the configuration first observed in K6P2W ,80 62-14 H 20 (D awson-structure). II was not known until now. It crystal lizes in the trigonal space group R 3 with lattice param eters a — b — 37.857(32). c = 13.108(13) Ä; a — ß = 90°, y = 120°. The structure of this anion differs from the D awson-structure by the 60° rotation of both polar groups of three W 0 6-octahedra (/3-type), followed by the 60° rotation of one of the two new AsWyO,,-units. Both rotations are about the 3-fold axis. The anion is centrosym m etric. Vibrational spectra and preparation of the isomers are described. | | | |
Reference
| Z. Naturforsch. 42b, 951—958 (1987); eingegangen am 4. März/11. Mai 1987 | | | |
Published
| 1987 | | | |
Keywords
| T ungstoarsenates, Isomers, X-Ray, V ibrational Spectra, Preparation | | | |
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| ZNB-1987-42b-0951 | | | | Volume
| 42 | |
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