Mg6HfC 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(3), two equivalent Mg(4), and one C(1) atom. In the second Mg site, Mg(2) is bonded in a 2-coordinate geometry to one Mg(3), one Mg(4), and two equivalent C(1) atoms. In the third Mg site, Mg(3) is bonded in a 8-coordinate geometry to two equivalent Mg(2), two equivalent Mg(4), and four equivalent Mg(1) atoms. In the fourth Mg site, Mg(4) is bonded in a 10-coordinate geometry to two equivalent Mg(2), two equivalent Mg(3), four equivalent Mg(1), and two equivalent Hf(1) atoms. Hf(1) is bonded in a distorted bent 150 degrees geometry to two equivalent Mg(4) 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 Hf(1) atoms.
Mg6HfC 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(3), two equivalent Mg(4), and one C(1) atom. Both Mg(1)-Mg(3) bond lengths are 3.29 Å. Both Mg(1)-Mg(4) bond lengths are 3.00 Å. The Mg(1)-C(1) bond length is 2.49 Å. In the second Mg site, Mg(2) is bonded in a 2-coordinate geometry to one Mg(3), one Mg(4), and two equivalent C(1) atoms. The Mg(2)-Mg(3) bond length is 2.94 Å. The Mg(2)-Mg(4) bond length is 3.15 Å. Both Mg(2)-C(1) bond lengths are 2.77 Å. In the third Mg site, Mg(3) is bonded in a 8-coordinate geometry to two equivalent Mg(2), two equivalent Mg(4), and four equivalent Mg(1) atoms. Both Mg(3)-Mg(4) bond lengths are 2.78 Å. In the fourth Mg site, Mg(4) is bonded in a 10-coordinate geometry to two equivalent Mg(2), two equivalent Mg(3), four equivalent Mg(1), and two equivalent Hf(1) atoms. Both Mg(4)-Hf(1) bond lengths are 3.02 Å. Hf(1) is bonded in a distorted bent 150 degrees geometry to two equivalent Mg(4) and two equivalent C(1) atoms. Both Hf(1)-C(1) bond lengths are 2.83 Å. C(1) is bonded in a 8-coordinate geometry to two equivalent Mg(1), four equivalent Mg(2), and two equivalent Hf(1) atoms.