DOI: 10.17188/1718018
title: Materials Data on Mg9Si5 by Materials Project

description: Mg9Si5 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are eighteen inequivalent Mg sites. In the first Mg site, Mg is bonded to one Mg and four Si atoms to form distorted MgMgSi4 tetrahedra that share a cornercorner with one SiMg8 hexagonal bipyramid, corners with two equivalent MgMgSi4 tetrahedra, and edges with two MgMgSi4 tetrahedra. The Mg–Mg bond length is 3.15 Å. There are a spread of Mg–Si bond distances ranging from 2.77–2.86 Å. In the second Mg site, Mg is bonded in a 4-coordinate geometry to one Mg and four Si atoms. The Mg–Mg bond length is 3.04 Å. There are a spread of Mg–Si bond distances ranging from 2.73–2.94 Å. In the third Mg site, Mg is bonded in a 3-coordinate geometry to three Si atoms. There are a spread of Mg–Si bond distances ranging from 2.62–2.79 Å. In the fourth 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 2.69–2.82 Å. In the fifth Mg site, Mg is bonded to one Mg and four Si atoms to form distorted MgMgSi4 tetrahedra that share a cornercorner with one SiMg8 hexagonal bipyramid, corners with three MgMgSi4 tetrahedra, and edges with two MgMgSi4 tetrahedra. The Mg–Mg bond length is 2.96 Å. There are a spread of Mg–Si bond distances ranging from 2.72–2.93 Å. In the sixth Mg site, Mg is bonded to four Si atoms to form a mixture of distorted corner and edge-sharing MgSi4 tetrahedra. There are a spread of Mg–Si bond distances ranging from 2.71–2.79 Å. In the seventh Mg site, Mg is bonded in a distorted T-shaped geometry to three Si atoms. There are a spread of Mg–Si bond distances ranging from 2.76–2.82 Å. In the eighth Mg site, Mg is bonded in a 5-coordinate geometry to five Si atoms. There are a spread of Mg–Si bond distances ranging from 2.67–2.94 Å. In the ninth Mg site, Mg is bonded in a 3-coordinate geometry to three Si atoms. There are a spread of Mg–Si bond distances ranging from 2.79–2.93 Å. In the tenth Mg site, Mg is bonded in a 3-coordinate geometry to one Mg and three Si atoms. The Mg–Mg bond length is 3.03 Å. There are a spread of Mg–Si bond distances ranging from 2.70–2.84 Å. In the eleventh Mg site, Mg is bonded in a 3-coordinate geometry to three Si atoms. There are two shorter (2.78 Å) and one longer (2.87 Å) Mg–Si bond lengths. In the twelfth Mg site, Mg is bonded in a 3-coordinate geometry to three Si atoms. There are a spread of Mg–Si bond distances ranging from 2.67–2.83 Å. In the thirteenth Mg site, Mg is bonded in a 5-coordinate geometry to five Si atoms. There are a spread of Mg–Si bond distances ranging from 2.78–2.87 Å. In the fourteenth Mg site, Mg is bonded in a 3-coordinate geometry to five Mg and five Si atoms. The Mg–Mg bond length is 3.16 Å. There are a spread of Mg–Si bond distances ranging from 2.66–3.05 Å. In the fifteenth Mg site, Mg is bonded in a 3-coordinate geometry to three Si atoms. There are a spread of Mg–Si bond distances ranging from 2.69–2.89 Å. In the sixteenth Mg site, Mg is bonded in a 3-coordinate geometry to one Mg and four Si atoms. There are a spread of Mg–Si bond distances ranging from 2.76–3.14 Å. In the seventeenth Mg site, Mg is bonded in a distorted trigonal non-coplanar geometry to three Si atoms. There are a spread of Mg–Si bond distances ranging from 2.76–2.83 Å. In the eighteenth Mg site, Mg is bonded in a 5-coordinate geometry to five Si atoms. There are a spread of Mg–Si bond distances ranging from 2.64–2.87 Å. There are ten inequivalent Si sites. In the first Si site, Si is bonded in a 8-coordinate geometry to seven Mg and one Si atom. The Si–Si bond length is 2.43 Å. In the second Si site, Si is bonded in a 8-coordinate geometry to eight Mg atoms. In the third Si site, Si is bonded in a 6-coordinate geometry to four Mg and two Si atoms. There are one shorter (2.41 Å) and one longer (2.45 Å) Si–Si bond lengths. In the fourth Si site, Si is bonded in a 8-coordinate geometry to six Mg and two Si atoms. The Si–Si bond length is 2.54 Å. In the fifth Si site, Si is bonded in a 7-coordinate geometry to seven Mg atoms. In the sixth Si site, Si is bonded in a 8-coordinate geometry to seven Mg and one Si atom. In the seventh Si site, Si is bonded in a 7-coordinate geometry to six Mg and one Si atom. In the eighth Si site, Si is bonded in a 8-coordinate geometry to seven Mg and one Si atom. In the ninth Si site, Si is bonded to eight Mg atoms to form distorted SiMg8 hexagonal bipyramids that share corners with two equivalent SiMg8 hexagonal bipyramids, corners with two MgMgSi4 tetrahedra, and an edgeedge with one SiMg8 hexagonal bipyramid. In the tenth Si site, Si is bonded to eight Mg atoms to form a mixture of distorted corner and edge-sharing SiMg8 hexagonal bipyramids.