Bi4Ge3O12 at the onset of pressure-induced amorphization.
The crystal structure of tetrabismuth tris(germanate), Bi4Ge3O12 (I43d, Z = 4), is stable to at least 7.30 GPa, as demonstrated by hydrostatic single-crystal X-ray diffraction measurements in a diamond anvil cell at room temperature. The highest pressure reached in this study is close to the onset of amorphization at about 8 GPa. The Bi and Ge atoms are located at the 16c (3) and 12a (4) Wyckoff positions, respectively. The compression mainly affects the distorted BiO6 octahedra, while the GeO4 tetrahedra are relatively rigid. When compared with the values obtained under ambient conditions, the long Bi-O distances decrease with increasing pressure, while the short Bi-O distances do not change.
Grzechnik
Andrzej
A
Departamento Física Materia Condensada, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Apartado 644, E-48080 Bilbao, Spain. andrzej.grzechnik@ehu.es