Mg14HfSb crystallizes in the orthorhombic Amm2 space group. There are seven inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(2), two equivalent Mg(6), four equivalent Mg(4), and four equivalent Mg(5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Hf(1)Mg10Sb2 cuboctahedra, corners with six equivalent Mg(1)Mg12 cuboctahedra, corners with eight equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with four equivalent Mg(6)Mg11Sb cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with eight equivalent Mg(5)HfMg10Sb cuboctahedra, faces with two equivalent Mg(6)Mg11Sb cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Sb(1)Hf2Mg10 cuboctahedra, faces with four equivalent Mg(5)HfMg10Sb cuboctahedra, faces with four equivalent Mg(4)Mg12 cuboctahedra, and faces with six equivalent Mg(7)HfMg11 cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(7), four equivalent Mg(4), and four equivalent Mg(5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Sb(1)Hf2Mg10 cuboctahedra, corners with six equivalent Mg(2)Mg12 cuboctahedra, corners with eight equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with four equivalent Mg(7)HfMg11 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with eight equivalent Mg(5)HfMg10Sb cuboctahedra, faces with two equivalent Mg(7)HfMg11 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Hf(1)Mg10Sb2 cuboctahedra, faces with four equivalent Mg(5)HfMg10Sb cuboctahedra, faces with four equivalent Mg(4)Mg12 cuboctahedra, and faces with six equivalent Mg(6)Mg11Sb cuboctahedra. In the third Mg site, Mg(3) is bonded to two equivalent Mg(3), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), two equivalent Hf(1), and two equivalent Sb(1) atoms to form distorted MgHf2Mg8Sb2 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with four equivalent Mg(2)Mg12 cuboctahedra, corners with four equivalent Mg(4)Mg12 cuboctahedra, corners with six equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, edges with two equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, edges with two equivalent Hf(1)Mg10Sb2 cuboctahedra, edges with two equivalent Sb(1)Hf2Mg10 cuboctahedra, edges with four equivalent Mg(5)HfMg10Sb cuboctahedra, edges with four equivalent Mg(7)HfMg11 cuboctahedra, edges with four equivalent Mg(6)Mg11Sb cuboctahedra, faces with two equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, faces with two equivalent Mg(7)HfMg11 cuboctahedra, faces with two equivalent Mg(6)Mg11Sb cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Hf(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Hf2Mg10 cuboctahedra, and faces with eight equivalent Mg(5)HfMg10Sb cuboctahedra. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), two equivalent Mg(5), two equivalent Mg(6), and two equivalent Mg(7) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, corners with four equivalent Hf(1)Mg10Sb2 cuboctahedra, corners with four equivalent Sb(1)Hf2Mg10 cuboctahedra, corners with six equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with two equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(5)HfMg10Sb cuboctahedra, edges with four equivalent Mg(7)HfMg11 cuboctahedra, edges with four equivalent Mg(6)Mg11Sb cuboctahedra, faces with two equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, faces with two equivalent Mg(7)HfMg11 cuboctahedra, faces with two equivalent Mg(6)Mg11Sb cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, and faces with eight equivalent Mg(5)HfMg10Sb cuboctahedra. In the fifth Mg site, Mg(5) is bonded to one Mg(1), one Mg(2), one Mg(3), one Mg(4), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), one Hf(1), and one Sb(1) atom to form distorted MgHfMg10Sb cuboctahedra that share corners with four equivalent Mg(7)HfMg11 cuboctahedra, corners with four equivalent Mg(6)Mg11Sb cuboctahedra, corners with ten equivalent Mg(5)HfMg10Sb cuboctahedra, edges with two equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, edges with two equivalent Mg(5)HfMg10Sb cuboctahedra, edges with two equivalent Mg(7)HfMg11 cuboctahedra, edges with two equivalent Mg(6)Mg11Sb cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with two equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Hf(1)Mg10Sb2 cuboctahedra, edges with two equivalent Sb(1)Hf2Mg10 cuboctahedra,  a faceface with one Mg(1)Mg12 cuboctahedra,  a faceface with one Mg(2)Mg12 cuboctahedra,  a faceface with one Hf(1)Mg10Sb2 cuboctahedra,  a faceface with one Sb(1)Hf2Mg10 cuboctahedra, faces with two equivalent Mg(7)HfMg11 cuboctahedra, faces with two equivalent Mg(6)Mg11Sb cuboctahedra, faces with four equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, faces with four equivalent Mg(5)HfMg10Sb cuboctahedra, and faces with four equivalent Mg(4)Mg12 cuboctahedra. In the sixth Mg site, Mg(6) is bonded to one Mg(1), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(7), four equivalent Mg(5), and one Sb(1) atom to form distorted MgMg11Sb cuboctahedra that share corners with four equivalent Mg(7)HfMg11 cuboctahedra, corners with six equivalent Mg(6)Mg11Sb cuboctahedra, corners with eight equivalent Mg(5)HfMg10Sb cuboctahedra, edges with two equivalent Mg(7)HfMg11 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with two equivalent Sb(1)Hf2Mg10 cuboctahedra, edges with four equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, edges with four equivalent Mg(5)HfMg10Sb cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra,  a faceface with one Mg(1)Mg12 cuboctahedra,  a faceface with one Sb(1)Hf2Mg10 cuboctahedra, faces with two equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, faces with two equivalent Mg(7)HfMg11 cuboctahedra, faces with two equivalent Mg(6)Mg11Sb cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with three equivalent Mg(2)Mg12 cuboctahedra, faces with three equivalent Hf(1)Mg10Sb2 cuboctahedra, and faces with four equivalent Mg(5)HfMg10Sb cuboctahedra. In the seventh Mg site, Mg(7) is bonded to one Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(6), four equivalent Mg(5), and one Hf(1) atom to form MgHfMg11 cuboctahedra that share corners with four equivalent Mg(6)Mg11Sb cuboctahedra, corners with six equivalent Mg(7)HfMg11 cuboctahedra, corners with eight equivalent Mg(5)HfMg10Sb cuboctahedra, edges with two equivalent Mg(6)Mg11Sb cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with two equivalent Hf(1)Mg10Sb2 cuboctahedra, edges with four equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, edges with four equivalent Mg(5)HfMg10Sb cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra,  a faceface with one Mg(2)Mg12 cuboctahedra,  a faceface with one Hf(1)Mg10Sb2 cuboctahedra, faces with two equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, faces with two equivalent Mg(7)HfMg11 cuboctahedra, faces with two equivalent Mg(6)Mg11Sb cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with three equivalent Mg(1)Mg12 cuboctahedra, faces with three equivalent Sb(1)Hf2Mg10 cuboctahedra, and faces with four equivalent Mg(5)HfMg10Sb cuboctahedra. Hf(1) is bonded to two equivalent Mg(7), four equivalent Mg(3), four equivalent Mg(5), and two equivalent Sb(1) atoms to form distorted HfMg10Sb2 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with six equivalent Hf(1)Mg10Sb2 cuboctahedra, corners with eight equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Sb(1)Hf2Mg10 cuboctahedra, edges with four equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, edges with four equivalent Mg(7)HfMg11 cuboctahedra, edges with eight equivalent Mg(5)HfMg10Sb cuboctahedra, faces with two equivalent Mg(7)HfMg11 cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Sb(1)Hf2Mg10 cuboctahedra, faces with four equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, faces with four equivalent Mg(5)HfMg10Sb cuboctahedra, and faces with six equivalent Mg(6)Mg11Sb cuboctahedra. Sb(1) is bonded to two equivalent Mg(6), four equivalent Mg(3), four equivalent Mg(5), and two equivalent Hf(1) atoms to form SbHf2Mg10 cuboctahedra that share corners with four equivalent Mg(2)Mg12 cuboctahedra, corners with six equivalent Sb(1)Hf2Mg10 cuboctahedra, corners with eight equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Hf(1)Mg10Sb2 cuboctahedra, edges with four equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, edges with four equivalent Mg(6)Mg11Sb cuboctahedra, edges with eight equivalent Mg(5)HfMg10Sb cuboctahedra, faces with two equivalent Mg(6)Mg11Sb cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Hf(1)Mg10Sb2 cuboctahedra, faces with four equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, faces with four equivalent Mg(5)HfMg10Sb cuboctahedra, and faces with six equivalent Mg(7)HfMg11 cuboctahedra.
Mg14HfSb crystallizes in the orthorhombic Amm2 space group. There are seven inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(2), two equivalent Mg(6), four equivalent Mg(4), and four equivalent Mg(5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Hf(1)Mg10Sb2 cuboctahedra, corners with six equivalent Mg(1)Mg12 cuboctahedra, corners with eight equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with four equivalent Mg(6)Mg11Sb cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with eight equivalent Mg(5)HfMg10Sb cuboctahedra, faces with two equivalent Mg(6)Mg11Sb cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Sb(1)Hf2Mg10 cuboctahedra, faces with four equivalent Mg(5)HfMg10Sb cuboctahedra, faces with four equivalent Mg(4)Mg12 cuboctahedra, and faces with six equivalent Mg(7)HfMg11 cuboctahedra. Both Mg(1)-Mg(2) bond lengths are 3.14 Å. Both Mg(1)-Mg(6) bond lengths are 3.18 Å. All Mg(1)-Mg(4) bond lengths are 3.20 Å. All Mg(1)-Mg(5) bond lengths are 3.17 Å. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(7), four equivalent Mg(4), and four equivalent Mg(5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Sb(1)Hf2Mg10 cuboctahedra, corners with six equivalent Mg(2)Mg12 cuboctahedra, corners with eight equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with four equivalent Mg(7)HfMg11 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with eight equivalent Mg(5)HfMg10Sb cuboctahedra, faces with two equivalent Mg(7)HfMg11 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Hf(1)Mg10Sb2 cuboctahedra, faces with four equivalent Mg(5)HfMg10Sb cuboctahedra, faces with four equivalent Mg(4)Mg12 cuboctahedra, and faces with six equivalent Mg(6)Mg11Sb cuboctahedra. Both Mg(2)-Mg(7) bond lengths are 3.18 Å. All Mg(2)-Mg(4) bond lengths are 3.20 Å. All Mg(2)-Mg(5) bond lengths are 3.14 Å. In the third Mg site, Mg(3) is bonded to two equivalent Mg(3), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), two equivalent Hf(1), and two equivalent Sb(1) atoms to form distorted MgHf2Mg8Sb2 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with four equivalent Mg(2)Mg12 cuboctahedra, corners with four equivalent Mg(4)Mg12 cuboctahedra, corners with six equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, edges with two equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, edges with two equivalent Hf(1)Mg10Sb2 cuboctahedra, edges with two equivalent Sb(1)Hf2Mg10 cuboctahedra, edges with four equivalent Mg(5)HfMg10Sb cuboctahedra, edges with four equivalent Mg(7)HfMg11 cuboctahedra, edges with four equivalent Mg(6)Mg11Sb cuboctahedra, faces with two equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, faces with two equivalent Mg(7)HfMg11 cuboctahedra, faces with two equivalent Mg(6)Mg11Sb cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Hf(1)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Hf2Mg10 cuboctahedra, and faces with eight equivalent Mg(5)HfMg10Sb cuboctahedra. There is one shorter (3.11 Å) and one longer (3.17 Å) Mg(3)-Mg(3) bond length. Both Mg(3)-Mg(5) bond lengths are 3.19 Å. Both Mg(3)-Mg(6) bond lengths are 3.17 Å. Both Mg(3)-Mg(7) bond lengths are 3.15 Å. There is one shorter (3.19 Å) and one longer (3.21 Å) Mg(3)-Hf(1) bond length. There is one shorter (3.19 Å) and one longer (3.21 Å) Mg(3)-Sb(1) bond length. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), two equivalent Mg(5), two equivalent Mg(6), and two equivalent Mg(7) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, corners with four equivalent Hf(1)Mg10Sb2 cuboctahedra, corners with four equivalent Sb(1)Hf2Mg10 cuboctahedra, corners with six equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with two equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(5)HfMg10Sb cuboctahedra, edges with four equivalent Mg(7)HfMg11 cuboctahedra, edges with four equivalent Mg(6)Mg11Sb cuboctahedra, faces with two equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, faces with two equivalent Mg(7)HfMg11 cuboctahedra, faces with two equivalent Mg(6)Mg11Sb cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, and faces with eight equivalent Mg(5)HfMg10Sb cuboctahedra. There is one shorter (3.13 Å) and one longer (3.14 Å) Mg(4)-Mg(4) bond length. Both Mg(4)-Mg(5) bond lengths are 3.17 Å. Both Mg(4)-Mg(6) bond lengths are 3.15 Å. Both Mg(4)-Mg(7) bond lengths are 3.18 Å. In the fifth Mg site, Mg(5) is bonded to one Mg(1), one Mg(2), one Mg(3), one Mg(4), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), one Hf(1), and one Sb(1) atom to form distorted MgHfMg10Sb cuboctahedra that share corners with four equivalent Mg(7)HfMg11 cuboctahedra, corners with four equivalent Mg(6)Mg11Sb cuboctahedra, corners with ten equivalent Mg(5)HfMg10Sb cuboctahedra, edges with two equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, edges with two equivalent Mg(5)HfMg10Sb cuboctahedra, edges with two equivalent Mg(7)HfMg11 cuboctahedra, edges with two equivalent Mg(6)Mg11Sb cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with two equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Hf(1)Mg10Sb2 cuboctahedra, edges with two equivalent Sb(1)Hf2Mg10 cuboctahedra,  a faceface with one Mg(1)Mg12 cuboctahedra,  a faceface with one Mg(2)Mg12 cuboctahedra,  a faceface with one Hf(1)Mg10Sb2 cuboctahedra,  a faceface with one Sb(1)Hf2Mg10 cuboctahedra, faces with two equivalent Mg(7)HfMg11 cuboctahedra, faces with two equivalent Mg(6)Mg11Sb cuboctahedra, faces with four equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, faces with four equivalent Mg(5)HfMg10Sb cuboctahedra, and faces with four equivalent Mg(4)Mg12 cuboctahedra. There is one shorter (3.10 Å) and one longer (3.18 Å) Mg(5)-Mg(5) bond length. There is one shorter (3.18 Å) and one longer (3.23 Å) Mg(5)-Mg(6) bond length. There is one shorter (3.18 Å) and one longer (3.22 Å) Mg(5)-Mg(7) bond length. The Mg(5)-Hf(1) bond length is 3.16 Å. The Mg(5)-Sb(1) bond length is 3.19 Å. In the sixth Mg site, Mg(6) is bonded to one Mg(1), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(7), four equivalent Mg(5), and one Sb(1) atom to form distorted MgMg11Sb cuboctahedra that share corners with four equivalent Mg(7)HfMg11 cuboctahedra, corners with six equivalent Mg(6)Mg11Sb cuboctahedra, corners with eight equivalent Mg(5)HfMg10Sb cuboctahedra, edges with two equivalent Mg(7)HfMg11 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with two equivalent Sb(1)Hf2Mg10 cuboctahedra, edges with four equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, edges with four equivalent Mg(5)HfMg10Sb cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra,  a faceface with one Mg(1)Mg12 cuboctahedra,  a faceface with one Sb(1)Hf2Mg10 cuboctahedra, faces with two equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, faces with two equivalent Mg(7)HfMg11 cuboctahedra, faces with two equivalent Mg(6)Mg11Sb cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with three equivalent Mg(2)Mg12 cuboctahedra, faces with three equivalent Hf(1)Mg10Sb2 cuboctahedra, and faces with four equivalent Mg(5)HfMg10Sb cuboctahedra. Both Mg(6)-Mg(7) bond lengths are 3.14 Å. The Mg(6)-Sb(1) bond length is 3.19 Å. In the seventh Mg site, Mg(7) is bonded to one Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(6), four equivalent Mg(5), and one Hf(1) atom to form MgHfMg11 cuboctahedra that share corners with four equivalent Mg(6)Mg11Sb cuboctahedra, corners with six equivalent Mg(7)HfMg11 cuboctahedra, corners with eight equivalent Mg(5)HfMg10Sb cuboctahedra, edges with two equivalent Mg(6)Mg11Sb cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with two equivalent Hf(1)Mg10Sb2 cuboctahedra, edges with four equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, edges with four equivalent Mg(5)HfMg10Sb cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra,  a faceface with one Mg(2)Mg12 cuboctahedra,  a faceface with one Hf(1)Mg10Sb2 cuboctahedra, faces with two equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, faces with two equivalent Mg(7)HfMg11 cuboctahedra, faces with two equivalent Mg(6)Mg11Sb cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with three equivalent Mg(1)Mg12 cuboctahedra, faces with three equivalent Sb(1)Hf2Mg10 cuboctahedra, and faces with four equivalent Mg(5)HfMg10Sb cuboctahedra. The Mg(7)-Hf(1) bond length is 3.17 Å. Hf(1) is bonded to two equivalent Mg(7), four equivalent Mg(3), four equivalent Mg(5), and two equivalent Sb(1) atoms to form distorted HfMg10Sb2 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with six equivalent Hf(1)Mg10Sb2 cuboctahedra, corners with eight equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Sb(1)Hf2Mg10 cuboctahedra, edges with four equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, edges with four equivalent Mg(7)HfMg11 cuboctahedra, edges with eight equivalent Mg(5)HfMg10Sb cuboctahedra, faces with two equivalent Mg(7)HfMg11 cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Sb(1)Hf2Mg10 cuboctahedra, faces with four equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, faces with four equivalent Mg(5)HfMg10Sb cuboctahedra, and faces with six equivalent Mg(6)Mg11Sb cuboctahedra. Both Hf(1)-Sb(1) bond lengths are 3.14 Å. Sb(1) is bonded to two equivalent Mg(6), four equivalent Mg(3), four equivalent Mg(5), and two equivalent Hf(1) atoms to form SbHf2Mg10 cuboctahedra that share corners with four equivalent Mg(2)Mg12 cuboctahedra, corners with six equivalent Sb(1)Hf2Mg10 cuboctahedra, corners with eight equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Hf(1)Mg10Sb2 cuboctahedra, edges with four equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, edges with four equivalent Mg(6)Mg11Sb cuboctahedra, edges with eight equivalent Mg(5)HfMg10Sb cuboctahedra, faces with two equivalent Mg(6)Mg11Sb cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Hf(1)Mg10Sb2 cuboctahedra, faces with four equivalent Mg(3)Hf2Mg8Sb2 cuboctahedra, faces with four equivalent Mg(5)HfMg10Sb cuboctahedra, and faces with six equivalent Mg(7)HfMg11 cuboctahedra.