The crystal structure of α-MgD2 under high pressure by neutron powder diffraction

✍ Scribed by Kohlmann, Holger; Zhao, Yusheng; Nicol, Malcolm F.; McClure, Jason

• Book ID: 120641416
• Publisher: Oldenbourg Wissenschaftsverlag
• Year: 2008
• Tongue: English
• Weight: 196 KB
• Volume: 223
• Category: Article
• ISSN: 2194-4946
• DOI: 10.1524/zkri.2008.1126

✦ Synopsis

Abstract

The crystal structure of rutile-type magnesium deuteride, α-MgD~2~, has been studied by in situ neutron powder diffraction at room temperature and pressures up to 9.3 GPa. The bulk modulus B
~0~ = 49(2) GPa is about half, the linear compressibilities (0.0063/GPa along a and 0.0041/GPa along c) are about twice and the variation of the free positional parameter x about six times the values for the isostructural magnesium fluoride, indicating the strong polarizability of the deuteride anion. Under pressure the MgD~6~ octahedra are more compressed (four Mg–D distances at 199(1), two at 173(1) pm) than at ambient pressure (195.1(1), 194.8(2) pm) and the structural arrangement becomes more CaCl~2~ like, although no structural phase transition has been observed.