Crystal structures of Ga X 3 ( X = Cl, Br, I) and AlI 3

✍ Scribed by Troyanov, Sergey I.; Krahl, Thoralf; Kemnitz, Erhard

• Book ID: 120063422
• Publisher: Oldenbourg Wissenschaftsverlag
• Year: 2004
• Tongue: English
• Weight: 148 KB
• Volume: 219
• Category: Article
• ISSN: 2194-4946
• DOI: 10.1524/zkri.219.2.88.26320

✦ Synopsis

Abstract

Crystal structures of Ga__X__
~3~ (X = Cl (I), Br (II), and I (III)) and AlI~3~ (IV) were determined at low temperature by single crystal X-ray crystallography. I is monoclinic, space group __C__2/m with a = 11.948(4), b = 6.855(3), c = 7.050(3) Å, β = 125.69(3)°, Z = 4, R
~1~ = 0.038. II–IV are isotypic to each other: II is monoclinic, space group __P__2~1~/c with a = 8.874(4), b = 5.637(2), c = 11.006(4) Å, β = 107.81(4)°, Z = 4, R
~1~ = 0.056; III: a = 9.584(3), b = 6.084(2), c = 11.839(4) Å, β = 107.78(3)°, R
~1~ = 0.044; IV: a = 9.591(3), b = 6.069(2), c = 11.902(3) Å, β = 108.05(3)°, R
~1~ = 0.046. The crystal structures I–IV are built of dimeric M
~2~
X
~6~ molecules consisting of two MX
~4~ tetrahedra sharing a common XX edge with shorter M-X (terminal) and longer M-X(bridging) distances. The structure of I can not be described in terms of the closest Cl packing, whereas the structures of II–IV are based on slightly distorted cubic closest packing of halogen atoms, which accounts for their strong tendency to twinning.