Materials Data on YMg6Si by Materials Project
Mg6YSi crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. there are four inequivalent Mg sites. In the first Mg site, Mg is bonded in a 1-coordinate geometry to eight Mg, two equivalent Y, and one Si atom. There are a spread of Mg–Mg bond distances ranging from 3.03–3.20 Å. There are one shorter (3.26 Å) and one longer (3.32 Å) Mg–Y bond lengths. The Mg–Si bond length is 3.15 Å. In the second Mg site, Mg is bonded in a 12-coordinate geometry to eight Mg, two equivalent Y, and two equivalent Si atoms. There are a spread of Mg–Mg bond distances ranging from 2.99–3.42 Å. Both Mg–Y bond lengths are 3.19 Å. Both Mg–Si bond lengths are 3.11 Å. In the third Mg site, Mg is bonded to ten Mg and two equivalent Y atoms to form distorted MgY2Mg10 cuboctahedra that share corners with six equivalent MgY2Mg10 cuboctahedra, edges with four equivalent YMg10Si2 cuboctahedra, faces with two equivalent MgY2Mg10 cuboctahedra, and faces with two equivalent YMg10Si2 cuboctahedra. Both Mg–Mg bond lengths are 3.04 Å. Both Mg–Y bond lengths are 3.16 Å. In the fourth Mg site, Mg is bonded in a 12-coordinate geometry to ten Mg and two equivalent Si atoms. Both Mg–Si bond lengths are 3.15 Å. Y is bonded to ten Mg and two equivalent Si atoms to form distorted YMg10Si2 cuboctahedra that share corners with six equivalent YMg10Si2 cuboctahedra, edges with four equivalent MgY2Mg10 cuboctahedra, faces with two equivalent MgY2Mg10 cuboctahedra, and faces with two equivalent YMg10Si2 cuboctahedra. Both Y–Si bond lengths are 3.04 Å. Si is bonded in a 10-coordinate geometry to eight Mg and two equivalent Y atoms.