On the distribution of tetrelide atoms (Si, Ge) in Gd5(SixGe1−x)4

✍ Scribed by Sumohan Misra; Gordon J. Miller

• Publisher: Elsevier Science
• Year: 2006
• Tongue: English
• Weight: 625 KB
• Volume: 179
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1016/j.jssc.2006.03.001

✦ Synopsis

A crystallographic study of the Si/Ge site preferences in the Si-rich regime of Gd 5 (Si x Ge 1Àx ) 4 and a crystal chemical analysis of these site preferences for the entire range is presented. The room temperature crystal structure of Gd 5 Si 4 as well as four pseudobinary phases, Gd 5 (Si x Ge 1Àx ) 4 for xX0:6, is reported. All structures are orthorhombic (space group Pnma), Gd 5 Si 4 -type and show decreasing volume as the Si concentration increases. Refinements of the site occupancies for the three crystallographic sites for Si/Ge atoms in the asymmetric unit reveal a nonrandom, but still incompletely ordered arrangement of Si and Ge atoms. The distribution of Si and Ge atoms at each site impacts the fractions of possible homonuclear and heteronuclear Si-Si, Si-Ge and Ge-Ge dimers in the various structures. This distribution correlates with the observed room temperature crystal structures for the entire series of Gd 5 (Si x Ge 1Àx ) 4 .