Mg6MoC crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 2-coordinate geometry to two equivalent Mg(2) and two equivalent Mo(1) atoms. In the second Mg site, Mg(2) is bonded in a 12-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mo(1), and two equivalent C(1) atoms. In the third Mg site, Mg(3) is bonded in a 2-coordinate geometry to four equivalent Mg(2) and two equivalent Mo(1) atoms. In the fourth Mg site, Mg(4) is bonded in a 2-coordinate geometry to four equivalent Mg(2) and two equivalent C(1) atoms. Mo(1) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent C(1) atoms to form a mixture of corner and face-sharing MoMg10C2 cuboctahedra. C(1) is bonded in a distorted see-saw-like geometry to two equivalent Mg(4), four equivalent Mg(2), and two equivalent Mo(1) atoms.
Mg6MoC crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 2-coordinate geometry to two equivalent Mg(2) and two equivalent Mo(1) atoms. Both Mg(1)-Mg(2) bond lengths are 2.91 Å. There is one shorter (2.99 Å) and one longer (3.05 Å) Mg(1)-Mo(1) bond length. In the second Mg site, Mg(2) is bonded in a 12-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mo(1), and two equivalent C(1) atoms. There is one shorter (2.70 Å) and one longer (2.82 Å) Mg(2)-Mg(2) bond length. There is one shorter (2.95 Å) and one longer (3.09 Å) Mg(2)-Mg(3) bond length. There is one shorter (2.83 Å) and one longer (3.21 Å) Mg(2)-Mg(4) bond length. Both Mg(2)-Mo(1) bond lengths are 2.95 Å. Both Mg(2)-C(1) bond lengths are 2.95 Å. In the third Mg site, Mg(3) is bonded in a 2-coordinate geometry to four equivalent Mg(2) and two equivalent Mo(1) atoms. Both Mg(3)-Mo(1) bond lengths are 2.86 Å. In the fourth Mg site, Mg(4) is bonded in a 2-coordinate geometry to four equivalent Mg(2) and two equivalent C(1) atoms. Both Mg(4)-C(1) bond lengths are 2.81 Å. Mo(1) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent C(1) atoms to form a mixture of corner and face-sharing MoMg10C2 cuboctahedra. Both Mo(1)-C(1) bond lengths are 2.76 Å. C(1) is bonded in a distorted see-saw-like geometry to two equivalent Mg(4), four equivalent Mg(2), and two equivalent Mo(1) atoms.