DOI: 10.17188/1745521
title: Materials Data on Mg5Si9 by Materials Project

description: Mg5Si9 is Magnesium tetraboride-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are ten inequivalent Mg sites. In the first Mg site, Mg is bonded in a 2-coordinate geometry to three Mg and ten Si atoms. There are a spread of Mg–Mg bond distances ranging from 3.02–3.32 Å. There are a spread of Mg–Si bond distances ranging from 2.71–3.11 Å. In the second Mg site, Mg is bonded in a 3-coordinate geometry to one Mg and four Si atoms. The Mg–Mg bond length is 3.15 Å. There are a spread of Mg–Si bond distances ranging from 2.81–3.12 Å. In the third Mg site, Mg is bonded in a 4-coordinate geometry to one Mg and six Si atoms. The Mg–Mg bond length is 3.02 Å. There are a spread of Mg–Si bond distances ranging from 2.73–3.18 Å. In the fourth Mg site, Mg is bonded in a 12-coordinate geometry to three Mg and nine Si atoms. The Mg–Mg bond length is 3.19 Å. There are a spread of Mg–Si bond distances ranging from 2.78–3.15 Å. In the fifth Mg site, Mg is bonded in a 5-coordinate geometry to one Mg and five Si atoms. There are a spread of Mg–Si bond distances ranging from 2.72–2.99 Å. In the sixth Mg site, Mg is bonded in a 4-coordinate geometry to one Mg and four Si atoms. There are a spread of Mg–Si bond distances ranging from 2.70–3.01 Å. In the seventh Mg site, Mg is bonded in a 8-coordinate geometry to one Mg and eight Si atoms. There are a spread of Mg–Si bond distances ranging from 2.80–3.06 Å. In the eighth Mg site, Mg is bonded in a 6-coordinate geometry to one Mg and six Si atoms. There are a spread of Mg–Si bond distances ranging from 2.77–2.93 Å. In the ninth Mg site, Mg is bonded in a 10-coordinate geometry to ten Si atoms. There are a spread of Mg–Si bond distances ranging from 2.79–3.11 Å. In the tenth Mg site, Mg is bonded in a 6-coordinate geometry to eight Si atoms. There are a spread of Mg–Si bond distances ranging from 2.77–3.27 Å. There are eighteen inequivalent Si sites. In the first Si site, Si is bonded in a 1-coordinate geometry to three Mg and four Si atoms. There are a spread of Si–Si bond distances ranging from 2.45–2.77 Å. In the second Si site, Si is bonded in a 2-coordinate geometry to four Mg and four Si atoms. There are a spread of Si–Si bond distances ranging from 2.45–2.80 Å. In the third Si site, Si is bonded to seven Mg and five Si atoms to form distorted corner-sharing SiMg7Si5 cuboctahedra. There are a spread of Si–Si bond distances ranging from 2.64–2.83 Å. In the fourth Si site, Si is bonded in a 6-coordinate geometry to three Mg and four Si atoms. There are a spread of Si–Si bond distances ranging from 2.46–2.76 Å. In the fifth Si site, Si is bonded in a 10-coordinate geometry to five Mg and five Si atoms. There are a spread of Si–Si bond distances ranging from 2.55–2.74 Å. In the sixth Si site, Si is bonded in a 6-coordinate geometry to two equivalent Mg and four Si atoms. There are a spread of Si–Si bond distances ranging from 2.40–2.58 Å. In the seventh Si site, Si is bonded in a 5-coordinate geometry to five Mg and three Si atoms. The Si–Si bond length is 2.59 Å. In the eighth Si site, Si is bonded in a 2-coordinate geometry to four Mg and four Si atoms. The Si–Si bond length is 2.45 Å. In the ninth Si site, Si is bonded in a 7-coordinate geometry to three Mg and four Si atoms. There are one shorter (2.43 Å) and one longer (2.76 Å) Si–Si bond lengths. In the tenth 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 eleventh Si site, Si is bonded in a 1-coordinate geometry to two Mg and three Si atoms. There are one shorter (2.42 Å) and one longer (2.48 Å) Si–Si bond lengths. In the twelfth Si site, Si is bonded in a 7-coordinate geometry to three Mg and four Si atoms. There are one shorter (2.45 Å) and one longer (2.47 Å) Si–Si bond lengths. In the thirteenth Si site, Si is bonded in a 9-coordinate geometry to five Mg and three Si atoms. In the fourteenth Si site, Si is bonded in a 6-coordinate geometry to three Mg and three Si atoms. In the fifteenth Si site, Si is bonded in a 8-coordinate geometry to three Mg and five Si atoms. In the sixteenth Si site, Si is bonded in a 8-coordinate geometry to four Mg and four Si atoms. In the seventeenth Si site, Si is bonded in a 2-coordinate geometry to two Mg and three Si atoms. The Si–Si bond length is 2.60 Å. In the eighteenth Si site, Si is bonded in a 9-coordinate geometry to six Mg and three Si atoms.