Materials Data on Mg2Si by Materials Project

Abstract

Mg2Si crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are five inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five Si4- atoms. There are a spread of Mg–Si bond distances ranging from 2.89–3.17 Å. In the second Mg2+ site, Mg2+ is bonded to four Si4- atoms to form MgSi4 tetrahedra that share corners with two equivalent MgSi4 tetrahedra, corners with four equivalent MgSi5 trigonal bipyramids, an edgeedge with one MgSi4 tetrahedra, and edges with three equivalent MgSi5 trigonal bipyramids. There are a spread of Mg–Si bond distances ranging from 2.63–2.77 Å. In the third Mg2+ site, Mg2+ is bonded to five Si4- atoms to form distorted MgSi5 trigonal bipyramids that share corners with four equivalent MgSi4 tetrahedra, edges with three equivalent MgSi4 tetrahedra, and edges with four equivalent MgSi5 trigonal bipyramids. There are a spread of Mg–Si bond distances ranging from 2.86–3.06 Å. In the fourth Mg2+ site, Mg2+ is bonded in a square co-planar geometry to four equivalent Si4- atoms. There are two shorter (2.71 Å) and two longer (2.74 Å) Mg–Si bond lengths. In the fifth Mg2+ site, Mg2+ is bonded in a square co-planar geometry to four Si4- atoms. There are two shorter (2.58 Å) and two longer (2.87 Å) Mg–Si bond lengths. There are two inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 9-coordinate geometry to nine Mg2+ atoms. In the second Si4- site, Si4- is bonded in a 9-coordinate geometry to nine Mg2+ atoms.