Mg6CeC crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a single-bond geometry to two equivalent Mg(2), two equivalent Mg(3), and one C(1) atom. In the second Mg site, Mg(2) is bonded in a 10-coordinate geometry to one Mg(3), one Mg(4), two equivalent Mg(1), two equivalent Mg(2), two equivalent Ce(1), and two equivalent C(1) atoms. In the third Mg site, Mg(3) is bonded in a 10-coordinate geometry to two equivalent Mg(2), two equivalent Mg(4), four equivalent Mg(1), and two equivalent Ce(1) atoms. In the fourth Mg site, Mg(4) is bonded in a 4-coordinate geometry to two equivalent Mg(2) and two equivalent Mg(3) atoms. Ce(1) is bonded in a 2-coordinate geometry to two equivalent Mg(3), four equivalent Mg(2), and two equivalent C(1) atoms. C(1) is bonded in a 8-coordinate geometry to two equivalent Mg(1), four equivalent Mg(2), and two equivalent Ce(1) atoms.
Mg6CeC crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a single-bond geometry to two equivalent Mg(2), two equivalent Mg(3), and one C(1) atom. Both Mg(1)-Mg(2) bond lengths are 2.97 Å. Both Mg(1)-Mg(3) bond lengths are 3.09 Å. The Mg(1)-C(1) bond length is 2.42 Å. In the second Mg site, Mg(2) is bonded in a 10-coordinate geometry to one Mg(3), one Mg(4), two equivalent Mg(1), two equivalent Mg(2), two equivalent Ce(1), and two equivalent C(1) atoms. The Mg(2)-Mg(3) bond length is 3.23 Å. The Mg(2)-Mg(4) bond length is 3.14 Å. There is one shorter (2.73 Å) and one longer (2.85 Å) Mg(2)-Mg(2) bond length. Both Mg(2)-Ce(1) bond lengths are 3.20 Å. Both Mg(2)-C(1) bond lengths are 2.83 Å. In the third Mg site, Mg(3) is bonded in a 10-coordinate geometry to two equivalent Mg(2), two equivalent Mg(4), four equivalent Mg(1), and two equivalent Ce(1) atoms. Both Mg(3)-Mg(4) bond lengths are 2.89 Å. Both Mg(3)-Ce(1) bond lengths are 3.23 Å. In the fourth Mg site, Mg(4) is bonded in a 4-coordinate geometry to two equivalent Mg(2) and two equivalent Mg(3) atoms. Ce(1) is bonded in a 2-coordinate geometry to two equivalent Mg(3), four equivalent Mg(2), and two equivalent C(1) atoms. Both Ce(1)-C(1) bond lengths are 3.01 Å. C(1) is bonded in a 8-coordinate geometry to two equivalent Mg(1), four equivalent Mg(2), and two equivalent Ce(1) atoms.