DOI: 10.17188/1666486
title: Materials Data on Mg7Si4 by Materials Project

description: Mg7Si4 crystallizes in the triclinic P1 space group. The structure is two-dimensional and consists of one Mg7Si4 sheet oriented in the (0, 0, 1) direction. there are fourteen inequivalent Mg sites. In the first Mg site, Mg is bonded in a distorted trigonal non-coplanar geometry to two Mg and three Si atoms. There are one shorter (3.02 Å) and one longer (3.19 Å) Mg–Mg bond lengths. There are one shorter (2.75 Å) and two longer (2.82 Å) Mg–Si bond lengths. In the second Mg site, Mg is bonded to four Mg and four Si atoms to form distorted MgMg4Si4 tetrahedra that share corners with two equivalent MgSi4 trigonal pyramids, an edgeedge with one MgSi4 trigonal pyramid, and faces with two equivalent MgMg4Si4 tetrahedra. There are a spread of Mg–Mg bond distances ranging from 3.09–3.26 Å. There are a spread of Mg–Si bond distances ranging from 2.68–2.84 Å. In the third Mg site, Mg is bonded in a 4-coordinate geometry to seven Mg and six Si atoms. There are a spread of Mg–Mg bond distances ranging from 3.00–3.24 Å. There are a spread of Mg–Si bond distances ranging from 2.92–3.17 Å. In the fourth Mg site, Mg is bonded in a 5-coordinate geometry to six Mg and seven Si atoms. The Mg–Mg bond length is 3.35 Å. There are a spread of Mg–Si bond distances ranging from 2.92–3.13 Å. In the fifth Mg site, Mg is bonded in a 4-coordinate geometry to five Si atoms. There are a spread of Mg–Si bond distances ranging from 2.78–3.18 Å. In the sixth Mg site, Mg is bonded in a 2-coordinate geometry to two Si atoms. There are one shorter (2.79 Å) and one longer (2.88 Å) Mg–Si bond lengths. In the seventh Mg site, Mg is bonded in a 6-coordinate geometry to six Si atoms. There are a spread of Mg–Si bond distances ranging from 2.88–3.08 Å. In the eighth Mg site, Mg is bonded in a distorted L-shaped geometry to two Si atoms. There are one shorter (2.74 Å) and one longer (2.80 Å) Mg–Si bond lengths. In the ninth Mg site, Mg is bonded in a 4-coordinate geometry to four Si atoms. There are a spread of Mg–Si bond distances ranging from 2.78–3.10 Å. In the tenth Mg site, Mg is bonded to four Si atoms to form distorted MgSi4 trigonal pyramids that share corners with two equivalent MgMg4Si4 tetrahedra, corners with two equivalent MgSi4 trigonal pyramids, and an edgeedge with one MgMg4Si4 tetrahedra. There are a spread of Mg–Si bond distances ranging from 2.67–3.00 Å. In the eleventh Mg site, Mg is bonded in a 6-coordinate geometry to six Si atoms. There are a spread of Mg–Si bond distances ranging from 2.87–3.09 Å. In the twelfth Mg site, Mg is bonded in a 4-coordinate geometry to four Si atoms. There are a spread of Mg–Si bond distances ranging from 2.77–2.85 Å. In the thirteenth Mg site, Mg is bonded in a distorted water-like geometry to one Mg and two equivalent Si atoms. There are one shorter (2.80 Å) and one longer (2.82 Å) Mg–Si bond lengths. In the fourteenth Mg site, Mg is bonded in a distorted water-like geometry to two Mg and two equivalent Si atoms. There are one shorter (2.74 Å) and one longer (2.78 Å) Mg–Si bond lengths. There are eight inequivalent Si sites. In the first Si site, Si is bonded in a 8-coordinate geometry to six Mg and two Si atoms. There are one shorter (2.45 Å) and one longer (2.47 Å) Si–Si bond lengths. In the second Si site, Si is bonded in a 9-coordinate geometry to eight Mg and one Si atom. The Si–Si bond length is 2.48 Å. In the third Si site, Si is bonded in a 9-coordinate geometry to nine Mg atoms. In the fourth Si site, Si is bonded in a 8-coordinate geometry to six Mg and two Si atoms. Both Si–Si bond lengths are 2.46 Å. In the fifth Si site, Si is bonded in a 9-coordinate geometry to seven Mg and two Si atoms. In the sixth Si site, Si is bonded in a 9-coordinate geometry to seven Mg and two Si atoms. The Si–Si bond length is 2.42 Å. In the seventh Si site, Si is bonded in a 9-coordinate geometry to eight Mg and one Si atom. In the eighth Si site, Si is bonded in a 8-coordinate geometry to six Mg and two Si atoms.