Materials Data on Mg5Si6 by Materials Project

Mg5Si6 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are five inequivalent Mg sites. In the first Mg site, Mg is bonded in a rectangular see-saw-like geometry to four Si atoms. There are a spread of Mg–Si bond distances ranging from 2.71–2.80 Å. In the second Mg site, Mg is bonded in a 5-coordinate geometry to seven Si atoms. There are a spread of Mg–Si bond distances ranging from 2.86–3.21 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 2.78–2.92 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 2.84–3.07 Å. In the fifth Mg site, Mg is bonded in a 2-coordinate geometry to nine Si atoms. There are a spread of Mg–Si bond distances ranging from 2.82–3.26 Å. There are six inequivalent Si sites. In the first Si site, Si is bonded in a 8-coordinate geometry to six Mg and two Si atoms. There are one shorter (2.40 Å) and one longer (2.41 Å) Si–Si bond lengths. In the second Si site, Si is bonded in a 8-coordinate geometry to six Mg and two Si atoms. The Si–Si bond length is 2.40 Å. In the third 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 2.48–2.51 Å. In the fourth Si site, Si is bonded to three Mg and four Si atoms to form a mixture of distorted edge and corner-sharing SiMg3Si4 hexagonal pyramids. There are a spread of Si–Si bond distances ranging from 2.37–2.60 Å. In the fifth Si site, Si is bonded in a 8-coordinate geometry to six Mg and two Si atoms. The Si–Si bond length is 2.41 Å. In the sixth Si site, Si is bonded in a 1-coordinate geometry to seven Mg and three equivalent Si atoms.