DOI: 10.17188/1722239
title: Materials Data on Mg4Si7 by Materials Project

description: Mg4Si7 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are eight inequivalent Mg sites. In the first Mg site, Mg is bonded in a 8-coordinate geometry to eight Si atoms. There are a spread of Mg–Si bond distances ranging from 2.69–2.98 Å. In the second Mg site, Mg is bonded to one Mg and four Si atoms to form distorted MgMgSi4 tetrahedra that share corners with two equivalent MgMgSi5 square pyramids and corners with two equivalent MgMgSi4 tetrahedra. The Mg–Mg bond length is 3.13 Å. There are a spread of Mg–Si bond distances ranging from 2.61–2.73 Å. In the third Mg site, Mg is bonded in a 4-coordinate geometry to two equivalent Mg and six Si atoms. There are one shorter (3.10 Å) and one longer (3.30 Å) Mg–Mg bond lengths. There are a spread of Mg–Si bond distances ranging from 2.71–3.21 Å. In the fourth Mg site, Mg is bonded to one Mg and five Si atoms to form distorted MgMgSi5 square pyramids that share a cornercorner with one SiMgSi3 tetrahedra, corners with two equivalent MgMgSi4 tetrahedra, and edges with two equivalent MgMgSi5 square pyramids. The Mg–Mg bond length is 2.91 Å. There are a spread of Mg–Si bond distances ranging from 2.79–2.87 Å. In the fifth Mg site, Mg is bonded in a 7-coordinate geometry to nine Si atoms. There are a spread of Mg–Si bond distances ranging from 2.74–3.15 Å. In the sixth Mg site, Mg is bonded in a 5-coordinate geometry to three Mg and seven Si atoms. There are a spread of Mg–Si bond distances ranging from 2.71–3.08 Å. In the seventh Mg site, Mg is bonded in a 9-coordinate geometry to one Mg and eight Si atoms. There are a spread of Mg–Si bond distances ranging from 2.66–3.06 Å. In the eighth 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 2.90–3.12 Å. There are fourteen inequivalent Si sites. In the first Si site, Si is bonded in a 9-coordinate geometry to five Mg and four Si atoms. There are a spread of Si–Si bond distances ranging from 2.41–2.59 Å. In the second Si site, Si is bonded to one Mg and three Si atoms to form distorted SiMgSi3 tetrahedra that share a cornercorner with one MgMgSi5 square pyramid. There are one shorter (2.38 Å) and two longer (2.41 Å) Si–Si bond lengths. In the third Si site, Si is bonded in a 6-coordinate geometry to two Mg and four Si atoms. The Si–Si bond length is 2.53 Å. In the fourth Si site, Si is bonded in a 6-coordinate geometry to three Mg and three Si atoms. There are one shorter (2.42 Å) and one longer (2.48 Å) Si–Si bond lengths. In the fifth Si site, Si is bonded in a 7-coordinate geometry to five Mg and two Si atoms. There are one shorter (2.42 Å) and one longer (2.47 Å) Si–Si bond lengths. In the sixth Si site, Si is bonded in a 8-coordinate geometry to six Mg and two Si atoms. The Si–Si bond length is 2.50 Å. In the seventh Si site, Si is bonded in a 6-coordinate geometry to two Mg and four Si atoms. The Si–Si bond length is 2.40 Å. In the eighth Si site, Si is bonded in a 6-coordinate geometry to three Mg and three Si atoms. There are one shorter (2.42 Å) and one longer (2.44 Å) Si–Si bond lengths. In the ninth Si site, Si is bonded in a 8-coordinate geometry to seven Mg and one Si atom. The Si–Si bond length is 2.31 Å. In the tenth Si site, Si is bonded in a 7-coordinate geometry to three Mg and four Si atoms. There are a spread of Si–Si bond distances ranging from 2.44–2.53 Å. In the eleventh Si site, Si is bonded in a 7-coordinate geometry to six Mg and one Si atom. In the twelfth Si site, Si is bonded in a 9-coordinate geometry to six Mg and three Si atoms. The Si–Si bond length is 2.43 Å. In the thirteenth Si site, Si is bonded in a 5-coordinate geometry to one Mg and four Si atoms. In the fourteenth Si site, Si is bonded in a 7-coordinate geometry to three Mg and four Si atoms.