Materials Data on Mg3Si4 by Materials Project

Mg3Si4 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are six 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 2.71–2.95 Å. In the second 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 2.70–3.06 Å. In the third 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 2.68–2.88 Å. In the fourth 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 2.72–2.81 Å. In the fifth 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 2.75–2.83 Å. In the sixth Mg site, Mg is bonded in a 12-coordinate geometry to eight Si atoms. There are a spread of Mg–Si bond distances ranging from 2.86–3.10 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. There are one shorter (2.49 Å) and one longer (2.50 Å) Si–Si bond lengths. In the second Si site, Si is bonded in a 8-coordinate geometry to three Mg and five Si atoms. There are a spread of Si–Si bond distances ranging from 2.39–2.55 Å. In the third Si site, Si is bonded in a 5-coordinate geometry to two equivalent Mg and three Si atoms. The Si–Si bond length is 2.39 Å. In the fourth Si site, Si is bonded in a 7-coordinate geometry to six Mg and one Si atom. In the fifth Si site, Si is bonded in a 7-coordinate geometry to five Mg and two equivalent Si atoms. There are one shorter (2.43 Å) and one longer (2.44 Å) Si–Si bond lengths. In the sixth Si site, Si is bonded to seven Mg atoms to form distorted face-sharing SiMg7 pentagonal bipyramids. In the seventh Si site, Si is bonded in a 5-coordinate geometry to three Mg and two Si atoms. The Si–Si bond length is 2.44 Å. In the eighth Si site, Si is bonded in a 7-coordinate geometry to four Mg and three Si atoms.