Compositional and structural variations in the ternary system Li – Al – Si

✍ Scribed by Spina, Laurent; Jia, Yong Zhong; Ducourant, Bernard; Tillard, Monique; Belin, Claude

• Book ID: 120631388
• Publisher: Oldenbourg Wissenschaftsverlag
• Year: 2003
• Tongue: English
• Weight: 325 KB
• Volume: 218
• Category: Article
• ISSN: 2194-4946
• DOI: 10.1524/zkri.218.11.740.20305

✦ Synopsis

Abstract

The Li–Al–Si ternary system has been investigated and four ternary phases characterized using both powder and single crystal X-ray diffraction data. LiAlSi and Li~7~Al~3~Si~4~ crystallize in the F__4̅3__m, cubic system, Li~18~Al~2~Si~6~ in tetragonal __I__4~1~/amd and Li~15~Al~3~Si~6~ in hexagonal __P__6~3~/m space group. The structure of LiAlSi (a = 5.94 Å), previously reported from powder data, has been confirmed. The new compound Li~7~Al~3~Si~4~ has been identified and, due to a higher lithium content, its cell parameter is slightly larger (a = 6.115 Å). The tetragonal cell (a = 6.179(1) Å, c = 12.199(4) Å) of Li~18~Al~2~Si~6~ may be considered as a (1 × 1 × 2) supercell of the cubic one. Structural variations are strongly correlated to compositional fluctuations and atomic substitutions, in every case the SI–Al network displays some covalent character. In the Li~15~Al~3~Si~6~ hexagonal cell, bonding is more covalent leading to a heterographite-like SI–Al network.