Tin flux synthesis of rare-earth metal silicide compounds RESi1.7 (RE = Dy, Ho): a novel ordered structure derived from the AlB2 type
✍ Scribed by Roger, Jérome; Babizhetskyy, Volodymyr; Jardin, Régis; Guérin, Roland; Moinet, Claude; Burkhardt, Ulrich; Halet, Jean-Francois
- Book ID
- 120650198
- Publisher
- Oldenbourg Wissenschaftsverlag
- Year
- 2006
- Tongue
- English
- Weight
- 282 KB
- Volume
- 221
- Category
- Article
- ISSN
- 2194-4946
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✦ Synopsis
Abstract
The binary rare-earth metal silicides RESi~1.7~ (RE = Dy, Ho) were prepared by tin flux synthesis between 800–1000 °C. Single crystals were obtained after electrochemical dissolving of molten ingots. Their crystal structures were determined from single-crystal X-ray data: orthorhombic symmetry, space group __Imm__2; unit cell parameters a = 19.144(1), b = 8.2562(3), c = 6.6571(3) Å and a = 19.063(1), b = 8.2120(2), c = 6.6313(2) Å for DySi~1.7~ and HoSi~1.7~, respectively. They represent a new ordered structure type, which is a derivative of the defect AlB~2~ type. The main structural feature is the occurrence of a vacancy ordering in the two-dimensional planar network of silicon atoms, leading to rows of edge-shared twelve-membered rings separated by distorted hexagonal rings. Structural comparison with the parent hexagonal silicide Yb~3~Si~5~ (Th~3~Pd~5~ type), the structure of which has been re-determined on single crystal, is also given.