The tau-borides tau-(Fe0.54Ir0.46)20Fe3B6 and tau-(Co0.64Ir0.36)21Co0.16B4B6
- Autor(en)
- Oksana Solohub, Oksana Sologub, Peter Franz Rogl, Gerald Giester
- Abstrakt
Two tau-borides, s-(Fe0.54Ir0.46)20Fe3B6 and s-(Co0.64Ir0.36)21Co0.16B4B6 were studied by X-ray powder andsingle crystal diffraction with respect to precise atom site distribution and metal atom ordering. X-raystructure determination for a single crystal of s-(Fe0.54Ir0.46)20Fe3B6 revealed isotypism with a partiallyordered Cr23C6-type (space group Fm3m, a ¼ 1.11020 nm) but with a high degree of random replacementof Fe/Ir atoms in sites 48h and 32f. X-ray single crystal data for s-(Co0.64Ir0.36)21Co0.16B4B6 showed a novellow-symmetry structure variant of tau-borides characterized by a noncentrosymmetric distribution ofboron tetrahedra and a defect Co-site (space group F4 3m as a translationengleiche, nonisomorphicmaximal subgroup of index 2 of Fm3m, a ¼ 1.09359 nm). The crystal structures of both s-phases aredescribed with nested polyhedra geometrically related to the a-Mn structure. Stability ranges andvarious structural arrangements of (MM’)23B6 phases are discussed.The crystal structures of (Fe1_xIrx)3B (x ¼ 0.24; X-ray single crystal data; Fe3C-type, space group Pnma,a ¼ 0.5430(2), b ¼ 0.6958(2) nm, c ¼ 0.4654(2) nm), and of isotypic (Fe1_xRhx)3B (XPD Rietveldrefinement, x ¼ 0.25, space group Pnma, a ¼ 0.54560(1) nm, b ¼ 0.69552(1) nm, c ¼ 0.46169(1) nm)show both a high degree of randomness in the metal sites.
- Organisation(en)
- Institut für Physikalische Chemie, Institut für Mineralogie und Kristallographie
- Externe Organisation(en)
- Instituto Superior Técnico
- Journal
- Intermetallics
- Band
- 18
- Seiten
- 694-701
- Anzahl der Seiten
- 8
- ISSN
- 0966-9795
- DOI
- https://doi.org/10.1016/j.intermet.2009.11.010
- Publikationsdatum
- 2010
- Peer-reviewed
- Ja
- ÖFOS 2012
- 104017 Physikalische Chemie, 105113 Kristallographie
- Link zum Portal
- https://ucrisportal.univie.ac.at/de/publications/4c06e269-7e58-4681-a4dd-b81fe61af4d6