Materials Data on CeMg6Al by Materials Project
Mg6CeAl 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 one Al atom. There are a spread of Mg–Mg bond distances ranging from 3.23–3.35 Å. There are one shorter (3.38 Å) and one longer (3.42 Å) Mg–Ce bond lengths. The Mg–Al bond length is 3.33 Å. In the second Mg site, Mg is bonded in a 12-coordinate geometry to eight Mg, two equivalent Ce, and two equivalent Al atoms. There are a spread of Mg–Mg bond distances ranging from 3.17–3.49 Å. Both Mg–Ce bond lengths are 3.30 Å. Both Mg–Al bond lengths are 3.21 Å. In the third Mg site, Mg is bonded to ten Mg and two equivalent Al atoms to form distorted MgMg10Al2 cuboctahedra that share corners with six equivalent MgMg10Al2 cuboctahedra, faces with two equivalent MgMg10Al2 cuboctahedra, and faces with six equivalent CeMg10Al2 cuboctahedra. Both Mg–Mg bond lengths are 3.30 Å. Both Mg–Al bond lengths are 3.29 Å. In the fourth Mg site, Mg is bonded in a 12-coordinate geometry to ten Mg and two equivalent Ce atoms. Both Mg–Ce bond lengths are 3.30 Å. Ce is bonded to ten Mg and two equivalent Al atoms to form CeMg10Al2 cuboctahedra that share corners with six equivalent CeMg10Al2 cuboctahedra, faces with two equivalent CeMg10Al2 cuboctahedra, and faces with six equivalent MgMg10Al2 cuboctahedra. Both Ce–Al bond lengths are 3.30 Å. Al is bonded in a 10-coordinate geometry to eight Mg and two equivalent Ce atoms.