Mg14SiSb 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 a mixture of corner, face, and edge-sharing MgMg12 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 a mixture of corner, face, and edge-sharing MgMg12 cuboctahedra. In the third Mg site, Mg(3) is bonded in a 12-coordinate geometry to two equivalent Mg(3), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), two equivalent Si(1), and two equivalent Sb(1) atoms. 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 a mixture of corner, face, and edge-sharing MgMg12 cuboctahedra. In the fifth Mg site, Mg(5) is bonded in a 2-coordinate geometry to one Mg(1), one Mg(2), one Mg(3), one Mg(4), one Si(1), and one Sb(1) atom. In the sixth Mg site, Mg(6) is bonded in a distorted single-bond geometry to one Mg(1), two equivalent Mg(3), two equivalent Mg(4), and one Si(1) atom. In the seventh Mg site, Mg(7) is bonded in a distorted single-bond geometry to one Mg(2), two equivalent Mg(3), two equivalent Mg(4), and one Sb(1) atom. Si(1) is bonded in a 10-coordinate geometry to two equivalent Mg(6), four equivalent Mg(3), and four equivalent Mg(5) atoms. Sb(1) is bonded in a 10-coordinate geometry to two equivalent Mg(7), four equivalent Mg(3), and four equivalent Mg(5) atoms.
Mg14SiSb 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 a mixture of corner, face, and edge-sharing MgMg12 cuboctahedra. Both Mg(1)-Mg(2) bond lengths are 3.26 Å. Both Mg(1)-Mg(6) bond lengths are 3.15 Å. There are two shorter (3.13 Å) and two longer (3.15 Å) Mg(1)-Mg(4) bond lengths. All Mg(1)-Mg(5) bond lengths are 3.16 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 a mixture of corner, face, and edge-sharing MgMg12 cuboctahedra. Both Mg(2)-Mg(7) bond lengths are 3.12 Å. There are two shorter (3.13 Å) and two longer (3.16 Å) Mg(2)-Mg(4) bond lengths. All Mg(2)-Mg(5) bond lengths are 3.19 Å. In the third Mg site, Mg(3) is bonded in a 12-coordinate geometry to two equivalent Mg(3), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), two equivalent Si(1), and two equivalent Sb(1) atoms. There is one shorter (3.26 Å) and one longer (3.27 Å) Mg(3)-Mg(3) bond length. Both Mg(3)-Mg(5) bond lengths are 3.10 Å. Both Mg(3)-Mg(6) bond lengths are 3.12 Å. Both Mg(3)-Mg(7) bond lengths are 3.17 Å. There is one shorter (3.10 Å) and one longer (3.18 Å) Mg(3)-Si(1) bond length. There is one shorter (3.11 Å) and one longer (3.18 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 a mixture of corner, face, and edge-sharing MgMg12 cuboctahedra. There is one shorter (3.26 Å) and one longer (3.27 Å) Mg(4)-Mg(4) bond length. Both Mg(4)-Mg(5) bond lengths are 3.16 Å. Both Mg(4)-Mg(6) bond lengths are 3.19 Å. Both Mg(4)-Mg(7) bond lengths are 3.14 Å. In the fifth Mg site, Mg(5) is bonded in a 2-coordinate geometry to one Mg(1), one Mg(2), one Mg(3), one Mg(4), one Si(1), and one Sb(1) atom. The Mg(5)-Si(1) bond length is 3.11 Å. The Mg(5)-Sb(1) bond length is 3.14 Å. In the sixth Mg site, Mg(6) is bonded in a distorted single-bond geometry to one Mg(1), two equivalent Mg(3), two equivalent Mg(4), and one Si(1) atom. The Mg(6)-Si(1) bond length is 3.05 Å. In the seventh Mg site, Mg(7) is bonded in a distorted single-bond geometry to one Mg(2), two equivalent Mg(3), two equivalent Mg(4), and one Sb(1) atom. The Mg(7)-Sb(1) bond length is 3.12 Å. Si(1) is bonded in a 10-coordinate geometry to two equivalent Mg(6), four equivalent Mg(3), and four equivalent Mg(5) atoms. Sb(1) is bonded in a 10-coordinate geometry to two equivalent Mg(7), four equivalent Mg(3), and four equivalent Mg(5) atoms.