The Atomic Order of the Pnictogen and Chalcogen Atoms in Equiatomic Ternary Compounds TPnCh (T=Ni, Pd; Pn=P, As, Sb; Ch=S, Se, Te)
✍ Scribed by Aloys J. Foecker; Wolfgang Jeitschko
- Publisher
- Elsevier Science
- Year
- 2001
- Tongue
- English
- Weight
- 370 KB
- Volume
- 162
- Category
- Article
- ISSN
- 0022-4596
No coin nor oath required. For personal study only.
✦ Synopsis
The crystal structures of the compounds NiAsS, NiSbS, PdAsS, PdAsSe, PdSbSe, and PdSbTe were re5ned from singlecrystal X-ray di4ractometer data. In these cubic compounds the pnictogen and chalcogen atoms show an ordered distribution corresponding to the ullmannite (NiSbS) type structure (space group P2 1 3, Z ؍ 4). By analogy this can be assumed for NiPS and NiAsSe, although for these compounds the structure re5nements did not make it possible to distinguish between a disordered distribution of the pnictogen and chalcogen atoms (corresponding to the pyrite structure) or an ordered distribution (corresponding to ullmannite or cobaltite). All atomic positions are fully occupied within the error limits of ؎ 2%. A re5nement from X-ray powder data established the ullmannite structure also for NiSbSe. The PdPS type structure of PdPSe was re5ned from single-crystal data. No equiatomic ternary compounds were observed in the ternary systems Ni+P+Se, Ni+P+Te, Ni+As+Te, Ni+Sb+Te, Pd+P+Te, and Pd+As+Te. A re5nement from singlecrystal data showed Ni 0.766(5) Sb 0.50(3) Te 0.50(3) to crystallize with a defect-NiAs type structure. Extended solid solutions were observed for the pseudobinary system NiP 2 +NiSe 2 , where a slowly cooled equiatomic sample contained NiP 1.86(4) Se 0.14(4) and NiP 0.24(4) Se 1.76(4) as limiting compositions, as shown by structure re5nements from X-ray powder data. Chemical bonding in these compounds is brie6y discussed.