Materials Data on MgSi2 by Materials Project

Abstract

MgSi2 crystallizes in the monoclinic Pm space group. The structure is three-dimensional. there are four inequivalent Mg sites. In the first 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 2.65–2.89 Å. In the second Mg site, Mg is bonded in a 9-coordinate geometry to nine Si atoms. There are a spread of Mg–Si bond distances ranging from 2.77–3.04 Å. In the third Mg site, Mg is bonded to six Si atoms to form distorted edge-sharing MgSi6 octahedra. There are a spread of Mg–Si bond distances ranging from 2.78–3.03 Å. In the fourth Mg site, Mg is bonded in a 7-coordinate geometry to seven Si atoms. There are a spread of Mg–Si bond distances ranging from 2.81–3.02 Å. There are eight inequivalent Si sites. In the first Si site, Si is bonded in a 8-coordinate geometry to six Mg and two equivalent Si atoms. Both Si–Si bond lengths are 2.43 Å. In the second Si site, Si is bonded in a 8-coordinate geometry to five Mg and three Si atoms. There are two shorter (2.44 Å) and one longer (2.47 Å) Si–Si bond lengths. In the third Si site, Si is bonded in a 6-coordinate geometry to three Mg and three Si atoms. Both Si–Si bond lengths are 2.38 Å. In the fourth Si site, Si is bonded in a 7-coordinate geometry to three Mg and three Si atoms. There are one shorter (2.40 Å) and two longer (2.43 Å) Si–Si bond lengths. In the fifth Si site, Si is bonded in a 6-coordinate geometry to three Mg and five Si atoms. There are one shorter (2.47 Å) and two longer (2.86 Å) Si–Si bond lengths. In the sixth Si site, Si is bonded to three Mg and three Si atoms to form distorted edge-sharing SiMg3Si3 octahedra. The Si–Si bond length is 2.46 Å. In the seventh Si site, Si is bonded in a 5-coordinate geometry to one Mg and four Si atoms. In the eighth Si site, Si is bonded in a 9-coordinate geometry to four Mg and five Si atoms.