High‐pressure synthesis and crystal structure of the strontium tungstate Sr3W2O9. Issue 2 (9th January 2018)

• Record Type: Journal Article
• Authors: Urushihara, Daisuke; Asaka, Toru; Fukuda, Koichiro; Sakurai, Hiroya
• Is Part Of: Acta crystallographica. Volume 74:Issue 2(2018)
• Page Start: 120
• Page End: 124
• Publication Date: 2018-01-09
• Subjects: electron diffraction -- polycrystalline material -- high‐pressure synthesis -- strontium tungstate -- crystal structure; Crystallography -- Periodicals; Crystals -- Periodicals; 548.3
• DOI: 10.1107/S2053229617017879
• Languages: English
• ISSNs: 2053-2296

Abstract

Abstract : The strontium tungstate Sr3 W2 O9 was obtained using a high‐pressure synthesis technique. The structure was found to be a hettotype structure of the high‐pressure phase of Ba3 W2 O9 . One characteristic of the structure is the breaking of the threefold rotation symmetry existing in the high‐pressure phase of Ba3 W2 O9 . Abstract : The strontium tungstate compound Sr3 W2 O9 was prepared by a high‐pressure synthesis technique. The crystal structure was determined by single‐crystal X‐ray diffraction and transmission electron microscopy. The structure was found to be a hettotype structure of the high‐pressure phase of Ba3 W2 O9, which has corner‐sharing octahedra with a trigonal symmetry. Sr3 W2 O9 has a monoclinic unit cell of C 2/ c symmetry. One characteristic of the structure is the breaking of the threefold rotation symmetry existing in the high‐pressure phase of Ba3 W2 O9 . The substitution of Sr at the Ba site results in a significant shortening of the interlayer distances of the [ A O3 ] layers ( A = Ba, Sr) and causes a distortion in the crystal structure. In Sr3 W2 O9, there is an off‐centre displacement of W 6+ ions in the WO6 octahedra. Such a displacement is also observed in the high‐pressure phase of Ba3 W2 O9 .