Materials Data on Mg11(Al2Cu)6 by Materials Project
Mg11(CuAl2)6 crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. there are five inequivalent Mg sites. In the first Mg site, Mg is bonded in a 12-coordinate geometry to four equivalent Mg and twelve equivalent Al atoms. All Mg–Mg bond lengths are 2.93 Å. All Mg–Al bond lengths are 3.19 Å. In the second Mg site, Mg is bonded in a 10-coordinate geometry to four equivalent Cu and six Al atoms. There are two shorter (2.91 Å) and two longer (2.98 Å) Mg–Cu bond lengths. There are two shorter (2.99 Å) and four longer (3.13 Å) Mg–Al bond lengths. In the third Mg site, Mg is bonded in a 3-coordinate geometry to one Mg, three equivalent Cu, and six equivalent Al atoms. The Mg–Mg bond length is 3.26 Å. All Mg–Cu bond lengths are 2.76 Å. All Mg–Al bond lengths are 3.12 Å. In the fourth Mg site, Mg is bonded in a 12-coordinate geometry to four equivalent Mg and twelve equivalent Al atoms. All Mg–Al bond lengths are 3.12 Å. In the fifth Mg site, Mg is bonded in a 8-coordinate geometry to two Mg and six equivalent Al atoms. The Mg–Mg bond length is 2.84 Å. All Mg–Al bond lengths are 3.00 Å. Cu is bonded in a 9-coordinate geometry to five Mg and four Al atoms. There are a spread of Cu–Al bond distances ranging from 2.43–2.56 Å. There are two inequivalent Al sites. In the first Al site, Al is bonded in a 11-coordinate geometry to five Mg, three equivalent Cu, and three equivalent Al atoms. There are one shorter (2.65 Å) and two longer (2.66 Å) Al–Al bond lengths. In the second Al site, Al is bonded in a distorted single-bond geometry to seven Mg and one Cu atom.