Structural investigation of the high pressure phases Si(vi), Ge(iv) and Sn.8In.2(II)

Abstract
The X-ray diffraction patterns of Si(VI) (at 39 GPa), Ge(IV) (at 113 GPa), and Sn8 In2 (II) (at 10 GPa) phases are interpreted on an orthorhombic cell. This cell is similar to that of the X-phase in Sn alloys, which also occurs between the primitive hexagonal and the hexagonal close packed phases. Structures in two space groups, Pnma and Pbcm, with Z = 4 can be fitted to the intensity data. In these the metal atoms have coordination close to 12.