Materials Data on CeMg6Si by Materials Project

Abstract

Mg6CeSi 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 12-coordinate geometry to eight Mg, two equivalent Ce, and two equivalent Si atoms. There are a spread of Mg–Mg bond distances ranging from 3.04–3.41 Å. There are one shorter (3.21 Å) and one longer (3.41 Å) Mg–Ce bond lengths. Both Mg–Si bond lengths are 3.14 Å. In the second Mg site, Mg is bonded to ten Mg and two equivalent Ce atoms to form distorted MgCe2Mg10 cuboctahedra that share corners with four equivalent CeMg10Si2 cuboctahedra, corners with six equivalent MgCe2Mg10 cuboctahedra, edges with two equivalent CeMg10Si2 cuboctahedra, edges with four equivalent MgMg10Si2 cuboctahedra, faces with two equivalent CeMg10Si2 cuboctahedra, and faces with four MgCe2Mg10 cuboctahedra. There are four shorter (3.08 Å) and two longer (3.13 Å) Mg–Mg bond lengths. Both Mg–Ce bond lengths are 3.29 Å. In the third Mg site, Mg is bonded in a 12-coordinate geometry to eight Mg, two equivalent Ce, and one Si atom. There are a spread of Mg–Mg bond distances ranging from 3.08–3.48 Å. Both Mg–Ce bond lengths are 3.25 Å. The Mg–Si bond length is 3.23 Å. In the fourth Mg site, Mg is bonded to ten Mg and two equivalent Si atoms to form distorted MgMg10Si2 cuboctahedra that share corners with six equivalent MgMg10Si2 cuboctahedra, edges with four equivalent MgCe2Mg10 cuboctahedra, faces with four MgCe2Mg10 cuboctahedra, and faces with six equivalent CeMg10Si2 cuboctahedra. Both Mg–Si bond lengths are 3.28 Å. Ce is bonded to ten Mg and two equivalent Si atoms to form distorted CeMg10Si2 cuboctahedra that share corners with four equivalent MgCe2Mg10 cuboctahedra, corners with six equivalent CeMg10Si2 cuboctahedra, edges with two equivalent MgCe2Mg10 cuboctahedra, faces with two equivalent CeMg10Si2 cuboctahedra, and faces with eight MgCe2Mg10 cuboctahedra. Both Ce–Si bond lengths are 3.00 Å. Si is bonded in a 2-coordinate geometry to eight Mg and two equivalent Ce atoms.