New family of phases, Li 2 MXO 4 : X = Zr, Hf; M = Mg, Mn, Fe, Co, Ni, Cu, Zn with α-LiFeO 2 and related structures
✍ Scribed by Castellanos, M.; Martinez, M. Chavez; West, A. R.
- Book ID
- 120565649
- Publisher
- Oldenbourg Wissenschaftsverlag
- Year
- 1990
- Tongue
- English
- Weight
- 698 KB
- Volume
- 190
- Category
- Article
- ISSN
- 2194-4946
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✦ Synopsis
Abstract
Thirteen new phases, Li~2~MXO~4~, have been synthesised. Nine of these, labelled α, with: M = Mg, Mn, Fe, Co, Zn, have the tetragonal α-LiFeO~2~, rock salt-related structure and are isostructural with previously reported Li~2~MgZrO~4~. In their structures, M and X ions are disordered over the octahedral Fe sites of α-LiFeO~2~. Three phases, labelled β, with: MX = NiHf, CuZr, CuHf, have closely related structures but with a lower symmetry space group and significantly different c/a ratios for their tetragonal unit cells. A structural model involving ordering of M and X ions is proposed in which the driving force for ordering is a Jahn-Teller distortion associated with Ni and Cu. Two phases: X = NiHf, NiZr, form other high temperature polymorphs which are also related structurally to rock salt but with varying degrees of cation disorder.