Mg6HfB 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), two equivalent Mg(4), and one B(1) atom. In the second Mg site, Mg(2) is bonded in a 10-coordinate geometry to two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(3) atoms. In the third Mg site, Mg(3) is bonded in a 10-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), and two equivalent Hf(1) atoms. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(2), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Hf(1) atoms to form a mixture of corner and face-sharing MgHf2Mg10 cuboctahedra. Hf(1) is bonded in a 2-coordinate geometry to two equivalent Mg(4), four equivalent Mg(3), and two equivalent B(1) atoms. B(1) is bonded in a 4-coordinate geometry to two equivalent Mg(1) and two equivalent Hf(1) atoms.
Mg6HfB 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), two equivalent Mg(4), and one B(1) atom. There is one shorter (3.09 Å) and one longer (3.24 Å) Mg(1)-Mg(2) bond length. Both Mg(1)-Mg(3) bond lengths are 2.99 Å. Both Mg(1)-Mg(4) bond lengths are 2.98 Å. The Mg(1)-B(1) bond length is 2.58 Å. In the second Mg site, Mg(2) is bonded in a 10-coordinate geometry to two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(3) atoms. Both Mg(2)-Mg(4) bond lengths are 2.94 Å. All Mg(2)-Mg(3) bond lengths are 3.02 Å. In the third Mg site, Mg(3) is bonded in a 10-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), and two equivalent Hf(1) atoms. There is one shorter (3.08 Å) and one longer (3.22 Å) Mg(3)-Mg(3) bond length. There is one shorter (3.12 Å) and one longer (3.21 Å) Mg(3)-Mg(4) bond length. There is one shorter (2.99 Å) and one longer (3.34 Å) Mg(3)-Hf(1) bond length. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(2), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Hf(1) atoms to form a mixture of corner and face-sharing MgHf2Mg10 cuboctahedra. Both Mg(4)-Hf(1) bond lengths are 3.16 Å. Hf(1) is bonded in a 2-coordinate geometry to two equivalent Mg(4), four equivalent Mg(3), and two equivalent B(1) atoms. Both Hf(1)-B(1) bond lengths are 2.55 Å. B(1) is bonded in a 4-coordinate geometry to two equivalent Mg(1) and two equivalent Hf(1) atoms.