LiMg9B20 is hexagonal omega structure-derived structured and crystallizes in the triclinic P-1 space group. Li(1) is bonded to two equivalent B(1), two equivalent B(3), two equivalent B(4), two equivalent B(5), two equivalent B(6), and two equivalent B(8) atoms to form LiB12 cuboctahedra that share edges with two equivalent Mg(3)B12 cuboctahedra, edges with two equivalent Mg(4)B12 cuboctahedra, edges with two equivalent Mg(5)B12 cuboctahedra, edges with six equivalent Mg(2)B12 cuboctahedra, faces with two equivalent Mg(1)B12 cuboctahedra, faces with two equivalent Mg(3)B12 cuboctahedra, faces with two equivalent Mg(4)B12 cuboctahedra, and faces with two equivalent Mg(5)B12 cuboctahedra. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent B(1), two equivalent B(2), two equivalent B(4), two equivalent B(5), two equivalent B(8), and two equivalent B(9) atoms to form MgB12 cuboctahedra that share edges with two equivalent Mg(2)B12 cuboctahedra, edges with two equivalent Mg(3)B12 cuboctahedra, edges with two equivalent Mg(5)B12 cuboctahedra, edges with six equivalent Mg(4)B12 cuboctahedra, faces with two equivalent Li(1)B12 cuboctahedra, faces with two equivalent Mg(2)B12 cuboctahedra, faces with two equivalent Mg(3)B12 cuboctahedra, and faces with two equivalent Mg(5)B12 cuboctahedra. In the second Mg site, Mg(2) is bonded to one B(1), one B(10), one B(2), one B(5), one B(6), one B(8), two equivalent B(4), two equivalent B(7), and two equivalent B(9) atoms to form MgB12 cuboctahedra that share  an edgeedge with one Mg(1)B12 cuboctahedra,  an edgeedge with one Mg(2)B12 cuboctahedra,  an edgeedge with one Mg(4)B12 cuboctahedra, edges with two equivalent Mg(5)B12 cuboctahedra, edges with three equivalent Li(1)B12 cuboctahedra, edges with four equivalent Mg(3)B12 cuboctahedra,  a faceface with one Mg(1)B12 cuboctahedra,  a faceface with one Mg(2)B12 cuboctahedra,  a faceface with one Mg(3)B12 cuboctahedra, faces with two equivalent Mg(5)B12 cuboctahedra, and faces with three equivalent Mg(4)B12 cuboctahedra. In the third Mg site, Mg(3) is bonded to one B(6), one B(7), one B(8), one B(9), two equivalent B(10), two equivalent B(2), two equivalent B(3), and two equivalent B(5) atoms to form MgB12 cuboctahedra that share  an edgeedge with one Li(1)B12 cuboctahedra,  an edgeedge with one Mg(1)B12 cuboctahedra,  an edgeedge with one Mg(3)B12 cuboctahedra, edges with two equivalent Mg(4)B12 cuboctahedra, edges with three equivalent Mg(5)B12 cuboctahedra, edges with four equivalent Mg(2)B12 cuboctahedra,  a faceface with one Li(1)B12 cuboctahedra,  a faceface with one Mg(1)B12 cuboctahedra,  a faceface with one Mg(2)B12 cuboctahedra,  a faceface with one Mg(3)B12 cuboctahedra, faces with two equivalent Mg(4)B12 cuboctahedra, and faces with two equivalent Mg(5)B12 cuboctahedra. In the fourth Mg site, Mg(4) is bonded to one B(1), one B(3), one B(4), one B(5), one B(7), one B(9), two equivalent B(10), two equivalent B(6), and two equivalent B(8) atoms to form MgB12 cuboctahedra that share  an edgeedge with one Li(1)B12 cuboctahedra,  an edgeedge with one Mg(2)B12 cuboctahedra,  an edgeedge with one Mg(4)B12 cuboctahedra, edges with two equivalent Mg(3)B12 cuboctahedra, edges with three equivalent Mg(1)B12 cuboctahedra, edges with four equivalent Mg(5)B12 cuboctahedra,  a faceface with one Li(1)B12 cuboctahedra,  a faceface with one Mg(4)B12 cuboctahedra,  a faceface with one Mg(5)B12 cuboctahedra, faces with two equivalent Mg(3)B12 cuboctahedra, and faces with three equivalent Mg(2)B12 cuboctahedra. In the fifth Mg site, Mg(5) is bonded to one B(10), one B(4), one B(6), one B(9), two equivalent B(1), two equivalent B(2), two equivalent B(3), and two equivalent B(7) atoms to form MgB12 cuboctahedra that share  an edgeedge with one Li(1)B12 cuboctahedra,  an edgeedge with one Mg(1)B12 cuboctahedra,  an edgeedge with one Mg(5)B12 cuboctahedra, edges with two equivalent Mg(2)B12 cuboctahedra, edges with three equivalent Mg(3)B12 cuboctahedra, edges with four equivalent Mg(4)B12 cuboctahedra,  a faceface with one Li(1)B12 cuboctahedra,  a faceface with one Mg(1)B12 cuboctahedra,  a faceface with one Mg(4)B12 cuboctahedra,  a faceface with one Mg(5)B12 cuboctahedra, faces with two equivalent Mg(2)B12 cuboctahedra, and faces with two equivalent Mg(3)B12 cuboctahedra. There are ten inequivalent B sites. In the first B site, B(1) is bonded in a 9-coordinate geometry to one Li(1), one Mg(1), one Mg(2), one Mg(4), two equivalent Mg(5), one B(2), one B(3), and one B(8) atom. In the second B site, B(2) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(2), two equivalent Mg(3), two equivalent Mg(5), one B(1), one B(3), and one B(5) atom. In the third B site, B(3) is bonded in a 9-coordinate geometry to one Li(1), one Mg(4), two equivalent Mg(3), two equivalent Mg(5), one B(1), one B(2), and one B(5) atom. In the fourth B site, B(4) is bonded in a 9-coordinate geometry to one Li(1), one Mg(1), one Mg(4), one Mg(5), two equivalent Mg(2), one B(5), one B(6), and one B(9) atom. In the fifth B site, B(5) is bonded in a 9-coordinate geometry to one Li(1), one Mg(1), one Mg(2), one Mg(4), two equivalent Mg(3), one B(2), one B(3), and one B(4) atom. In the sixth B site, B(6) is bonded in a 9-coordinate geometry to one Li(1), one Mg(2), one Mg(3), one Mg(5), two equivalent Mg(4), one B(4), one B(7), and one B(8) atom. In the seventh B site, B(7) is bonded in a 9-coordinate geometry to one Mg(3), one Mg(4), two equivalent Mg(2), two equivalent Mg(5), one B(10), one B(6), and one B(7) atom. In the eighth B site, B(8) is bonded in a 9-coordinate geometry to one Li(1), one Mg(1), one Mg(2), one Mg(3), two equivalent Mg(4), one B(1), one B(6), and one B(9) atom. In the ninth B site, B(9) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(3), one Mg(4), one Mg(5), two equivalent Mg(2), one B(10), one B(4), and one B(8) atom. In the tenth B site, B(10) is bonded in a 9-coordinate geometry to one Mg(2), one Mg(5), two equivalent Mg(3), two equivalent Mg(4), one B(10), one B(7), and one B(9) atom.
LiMg9B20 is hexagonal omega structure-derived structured and crystallizes in the triclinic P-1 space group. Li(1) is bonded to two equivalent B(1), two equivalent B(3), two equivalent B(4), two equivalent B(5), two equivalent B(6), and two equivalent B(8) atoms to form LiB12 cuboctahedra that share edges with two equivalent Mg(3)B12 cuboctahedra, edges with two equivalent Mg(4)B12 cuboctahedra, edges with two equivalent Mg(5)B12 cuboctahedra, edges with six equivalent Mg(2)B12 cuboctahedra, faces with two equivalent Mg(1)B12 cuboctahedra, faces with two equivalent Mg(3)B12 cuboctahedra, faces with two equivalent Mg(4)B12 cuboctahedra, and faces with two equivalent Mg(5)B12 cuboctahedra. Both Li(1)-B(1) bond lengths are 2.50 Å. Both Li(1)-B(3) bond lengths are 2.49 Å. Both Li(1)-B(4) bond lengths are 2.50 Å. Both Li(1)-B(5) bond lengths are 2.49 Å. Both Li(1)-B(6) bond lengths are 2.48 Å. Both Li(1)-B(8) bond lengths are 2.48 Å. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent B(1), two equivalent B(2), two equivalent B(4), two equivalent B(5), two equivalent B(8), and two equivalent B(9) atoms to form MgB12 cuboctahedra that share edges with two equivalent Mg(2)B12 cuboctahedra, edges with two equivalent Mg(3)B12 cuboctahedra, edges with two equivalent Mg(5)B12 cuboctahedra, edges with six equivalent Mg(4)B12 cuboctahedra, faces with two equivalent Li(1)B12 cuboctahedra, faces with two equivalent Mg(2)B12 cuboctahedra, faces with two equivalent Mg(3)B12 cuboctahedra, and faces with two equivalent Mg(5)B12 cuboctahedra. Both Mg(1)-B(1) bond lengths are 2.50 Å. Both Mg(1)-B(2) bond lengths are 2.49 Å. Both Mg(1)-B(4) bond lengths are 2.49 Å. Both Mg(1)-B(5) bond lengths are 2.50 Å. Both Mg(1)-B(8) bond lengths are 2.50 Å. Both Mg(1)-B(9) bond lengths are 2.48 Å. In the second Mg site, Mg(2) is bonded to one B(1), one B(10), one B(2), one B(5), one B(6), one B(8), two equivalent B(4), two equivalent B(7), and two equivalent B(9) atoms to form MgB12 cuboctahedra that share  an edgeedge with one Mg(1)B12 cuboctahedra,  an edgeedge with one Mg(2)B12 cuboctahedra,  an edgeedge with one Mg(4)B12 cuboctahedra, edges with two equivalent Mg(5)B12 cuboctahedra, edges with three equivalent Li(1)B12 cuboctahedra, edges with four equivalent Mg(3)B12 cuboctahedra,  a faceface with one Mg(1)B12 cuboctahedra,  a faceface with one Mg(2)B12 cuboctahedra,  a faceface with one Mg(3)B12 cuboctahedra, faces with two equivalent Mg(5)B12 cuboctahedra, and faces with three equivalent Mg(4)B12 cuboctahedra. The Mg(2)-B(1) bond length is 2.49 Å. The Mg(2)-B(10) bond length is 2.51 Å. The Mg(2)-B(2) bond length is 2.49 Å. The Mg(2)-B(5) bond length is 2.50 Å. The Mg(2)-B(6) bond length is 2.51 Å. The Mg(2)-B(8) bond length is 2.50 Å. Both Mg(2)-B(4) bond lengths are 2.50 Å. Both Mg(2)-B(7) bond lengths are 2.50 Å. Both Mg(2)-B(9) bond lengths are 2.49 Å. In the third Mg site, Mg(3) is bonded to one B(6), one B(7), one B(8), one B(9), two equivalent B(10), two equivalent B(2), two equivalent B(3), and two equivalent B(5) atoms to form MgB12 cuboctahedra that share  an edgeedge with one Li(1)B12 cuboctahedra,  an edgeedge with one Mg(1)B12 cuboctahedra,  an edgeedge with one Mg(3)B12 cuboctahedra, edges with two equivalent Mg(4)B12 cuboctahedra, edges with three equivalent Mg(5)B12 cuboctahedra, edges with four equivalent Mg(2)B12 cuboctahedra,  a faceface with one Li(1)B12 cuboctahedra,  a faceface with one Mg(1)B12 cuboctahedra,  a faceface with one Mg(2)B12 cuboctahedra,  a faceface with one Mg(3)B12 cuboctahedra, faces with two equivalent Mg(4)B12 cuboctahedra, and faces with two equivalent Mg(5)B12 cuboctahedra. The Mg(3)-B(6) bond length is 2.49 Å. The Mg(3)-B(7) bond length is 2.51 Å. The Mg(3)-B(8) bond length is 2.48 Å. The Mg(3)-B(9) bond length is 2.50 Å. Both Mg(3)-B(10) bond lengths are 2.50 Å. Both Mg(3)-B(2) bond lengths are 2.50 Å. There is one shorter (2.48 Å) and one longer (2.51 Å) Mg(3)-B(3) bond length. There is one shorter (2.48 Å) and one longer (2.51 Å) Mg(3)-B(5) bond length. In the fourth Mg site, Mg(4) is bonded to one B(1), one B(3), one B(4), one B(5), one B(7), one B(9), two equivalent B(10), two equivalent B(6), and two equivalent B(8) atoms to form MgB12 cuboctahedra that share  an edgeedge with one Li(1)B12 cuboctahedra,  an edgeedge with one Mg(2)B12 cuboctahedra,  an edgeedge with one Mg(4)B12 cuboctahedra, edges with two equivalent Mg(3)B12 cuboctahedra, edges with three equivalent Mg(1)B12 cuboctahedra, edges with four equivalent Mg(5)B12 cuboctahedra,  a faceface with one Li(1)B12 cuboctahedra,  a faceface with one Mg(4)B12 cuboctahedra,  a faceface with one Mg(5)B12 cuboctahedra, faces with two equivalent Mg(3)B12 cuboctahedra, and faces with three equivalent Mg(2)B12 cuboctahedra. The Mg(4)-B(1) bond length is 2.49 Å. The Mg(4)-B(3) bond length is 2.47 Å. The Mg(4)-B(4) bond length is 2.49 Å. The Mg(4)-B(5) bond length is 2.48 Å. The Mg(4)-B(7) bond length is 2.51 Å. The Mg(4)-B(9) bond length is 2.51 Å. There is one shorter (2.50 Å) and one longer (2.51 Å) Mg(4)-B(10) bond length. There is one shorter (2.48 Å) and one longer (2.50 Å) Mg(4)-B(6) bond length. There is one shorter (2.49 Å) and one longer (2.50 Å) Mg(4)-B(8) bond length. In the fifth Mg site, Mg(5) is bonded to one B(10), one B(4), one B(6), one B(9), two equivalent B(1), two equivalent B(2), two equivalent B(3), and two equivalent B(7) atoms to form MgB12 cuboctahedra that share  an edgeedge with one Li(1)B12 cuboctahedra,  an edgeedge with one Mg(1)B12 cuboctahedra,  an edgeedge with one Mg(5)B12 cuboctahedra, edges with two equivalent Mg(2)B12 cuboctahedra, edges with three equivalent Mg(3)B12 cuboctahedra, edges with four equivalent Mg(4)B12 cuboctahedra,  a faceface with one Li(1)B12 cuboctahedra,  a faceface with one Mg(1)B12 cuboctahedra,  a faceface with one Mg(4)B12 cuboctahedra,  a faceface with one Mg(5)B12 cuboctahedra, faces with two equivalent Mg(2)B12 cuboctahedra, and faces with two equivalent Mg(3)B12 cuboctahedra. The Mg(5)-B(10) bond length is 2.52 Å. The Mg(5)-B(4) bond length is 2.48 Å. The Mg(5)-B(6) bond length is 2.49 Å. The Mg(5)-B(9) bond length is 2.50 Å. There is one shorter (2.48 Å) and one longer (2.51 Å) Mg(5)-B(1) bond length. There is one shorter (2.49 Å) and one longer (2.50 Å) Mg(5)-B(2) bond length. There is one shorter (2.49 Å) and one longer (2.51 Å) Mg(5)-B(3) bond length. There is one shorter (2.49 Å) and one longer (2.50 Å) Mg(5)-B(7) bond length. There are ten inequivalent B sites. In the first B site, B(1) is bonded in a 9-coordinate geometry to one Li(1), one Mg(1), one Mg(2), one Mg(4), two equivalent Mg(5), one B(2), one B(3), and one B(8) atom. The B(1)-B(2) bond length is 1.77 Å. The B(1)-B(3) bond length is 1.77 Å. The B(1)-B(8) bond length is 1.77 Å. In the second B site, B(2) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(2), two equivalent Mg(3), two equivalent Mg(5), one B(1), one B(3), and one B(5) atom. The B(2)-B(3) bond length is 1.78 Å. The B(2)-B(5) bond length is 1.78 Å. In the third B site, B(3) is bonded in a 9-coordinate geometry to one Li(1), one Mg(4), two equivalent Mg(3), two equivalent Mg(5), one B(1), one B(2), and one B(5) atom. The B(3)-B(5) bond length is 1.76 Å. In the fourth B site, B(4) is bonded in a 9-coordinate geometry to one Li(1), one Mg(1), one Mg(4), one Mg(5), two equivalent Mg(2), one B(5), one B(6), and one B(9) atom. The B(4)-B(5) bond length is 1.77 Å. The B(4)-B(6) bond length is 1.77 Å. The B(4)-B(9) bond length is 1.77 Å. In the fifth B site, B(5) is bonded in a 9-coordinate geometry to one Li(1), one Mg(1), one Mg(2), one Mg(4), two equivalent Mg(3), one B(2), one B(3), and one B(4) atom. In the sixth B site, B(6) is bonded in a 9-coordinate geometry to one Li(1), one Mg(2), one Mg(3), one Mg(5), two equivalent Mg(4), one B(4), one B(7), and one B(8) atom. The B(6)-B(7) bond length is 1.79 Å. The B(6)-B(8) bond length is 1.75 Å. In the seventh B site, B(7) is bonded in a 9-coordinate geometry to one Mg(3), one Mg(4), two equivalent Mg(2), two equivalent Mg(5), one B(10), one B(6), and one B(7) atom. The B(7)-B(10) bond length is 1.77 Å. The B(7)-B(7) bond length is 1.76 Å. In the eighth B site, B(8) is bonded in a 9-coordinate geometry to one Li(1), one Mg(1), one Mg(2), one Mg(3), two equivalent Mg(4), one B(1), one B(6), and one B(9) atom. The B(8)-B(9) bond length is 1.78 Å. In the ninth B site, B(9) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(3), one Mg(4), one Mg(5), two equivalent Mg(2), one B(10), one B(4), and one B(8) atom. The B(9)-B(10) bond length is 1.79 Å. In the tenth B site, B(10) is bonded in a 9-coordinate geometry to one Mg(2), one Mg(5), two equivalent Mg(3), two equivalent Mg(4), one B(10), one B(7), and one B(9) atom. The B(10)-B(10) bond length is 1.76 Å.