Mg23Ce6As crystallizes in the cubic Fm-3m space group. There are four inequivalent Mg sites. In the first Mg site, Mg(2) is bonded in a 10-coordinate geometry to one Mg(4), three equivalent Mg(1), three equivalent Mg(3), and three equivalent Ce(1) atoms. In the second Mg site, Mg(3) is bonded to four equivalent Mg(1), four equivalent Mg(2), and four equivalent Ce(1) atoms to form MgCe4Mg8 cuboctahedra that share corners with four equivalent Mg(3)Ce4Mg8 cuboctahedra, edges with two equivalent As(1)Ce6 octahedra, and faces with eight equivalent Mg(3)Ce4Mg8 cuboctahedra. In the third Mg site, Mg(4) is bonded in a body-centered cubic geometry to eight equivalent Mg(2) atoms. In the fourth Mg site, Mg(1) is bonded in a distorted q6 geometry to three equivalent Mg(1), three equivalent Mg(2), three equivalent Mg(3), and three equivalent Ce(1) atoms. Ce(1) is bonded in a single-bond geometry to four equivalent Mg(1), four equivalent Mg(2), four equivalent Mg(3), and one As(1) atom. As(1) is bonded to six equivalent Ce(1) atoms to form AsCe6 octahedra that share edges with twelve equivalent Mg(3)Ce4Mg8 cuboctahedra.
Mg23Ce6As crystallizes in the cubic Fm-3m space group. There are four inequivalent Mg sites. In the first Mg site, Mg(2) is bonded in a 10-coordinate geometry to one Mg(4), three equivalent Mg(1), three equivalent Mg(3), and three equivalent Ce(1) atoms. The Mg(2)-Mg(4) bond length is 3.08 Å. All Mg(2)-Mg(1) bond lengths are 3.16 Å. All Mg(2)-Mg(3) bond lengths are 3.17 Å. All Mg(2)-Ce(1) bond lengths are 3.56 Å. In the second Mg site, Mg(3) is bonded to four equivalent Mg(1), four equivalent Mg(2), and four equivalent Ce(1) atoms to form MgCe4Mg8 cuboctahedra that share corners with four equivalent Mg(3)Ce4Mg8 cuboctahedra, edges with two equivalent As(1)Ce6 octahedra, and faces with eight equivalent Mg(3)Ce4Mg8 cuboctahedra. All Mg(3)-Mg(1) bond lengths are 2.97 Å. All Mg(3)-Ce(1) bond lengths are 3.69 Å. In the third Mg site, Mg(4) is bonded in a body-centered cubic geometry to eight equivalent Mg(2) atoms. In the fourth Mg site, Mg(1) is bonded in a distorted q6 geometry to three equivalent Mg(1), three equivalent Mg(2), three equivalent Mg(3), and three equivalent Ce(1) atoms. All Mg(1)-Mg(1) bond lengths are 3.22 Å. All Mg(1)-Ce(1) bond lengths are 3.56 Å. Ce(1) is bonded in a single-bond geometry to four equivalent Mg(1), four equivalent Mg(2), four equivalent Mg(3), and one As(1) atom. The Ce(1)-As(1) bond length is 2.98 Å. As(1) is bonded to six equivalent Ce(1) atoms to form AsCe6 octahedra that share edges with twelve equivalent Mg(3)Ce4Mg8 cuboctahedra.