Materials Data on Si7Ge by Materials Project
GeSi7 is Moissanite 9R-like structured and crystallizes in the cubic P-43m space group. The structure is three-dimensional. Ge4+ is bonded to four equivalent Si+0.57- atoms to form GeSi4 tetrahedra that share corners with twelve equivalent SiSi4 tetrahedra. All Ge–Si bond lengths are 2.41 Å. There are two inequivalent Si+0.57- sites. In the first Si+0.57- site, Si+0.57- is bonded to one Ge4+ and three equivalent Si+0.57- atoms to form corner-sharing SiSi3Ge tetrahedra. All Si–Si bond lengths are 2.37 Å. In the second Si+0.57- site, Si+0.57- is bonded to four equivalent Si+0.57- atoms to form SiSi4 tetrahedra that share corners with four equivalent GeSi4 tetrahedra and corners with eight equivalent SiSi4 tetrahedra.
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