CaMg6Sb crystallizes in the orthorhombic Amm2 space group. Ca(1) is bonded to two equivalent Mg(2), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Sb(1) atoms to form CaMg10Sb2 cuboctahedra that share corners with four equivalent Mg(2)Ca2Mg10 cuboctahedra, corners with six equivalent Ca(1)Mg10Sb2 cuboctahedra, edges with two equivalent Mg(2)Ca2Mg10 cuboctahedra, edges with four equivalent Sb(1)Ca2Mg10 cuboctahedra, faces with two equivalent Ca(1)Mg10Sb2 cuboctahedra, faces with two equivalent Mg(2)Ca2Mg10 cuboctahedra, faces with two equivalent Sb(1)Ca2Mg10 cuboctahedra, and faces with six equivalent Mg(4)Mg10Sb2 cuboctahedra. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 12-coordinate geometry to two equivalent Ca(1), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), and two equivalent Sb(1) atoms. In the second Mg site, Mg(2) is bonded to two equivalent Ca(1), two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(3) atoms to form MgCa2Mg10 cuboctahedra that share corners with four equivalent Ca(1)Mg10Sb2 cuboctahedra, corners with six equivalent Mg(2)Ca2Mg10 cuboctahedra, edges with two equivalent Ca(1)Mg10Sb2 cuboctahedra, edges with four equivalent Mg(4)Mg10Sb2 cuboctahedra, faces with two equivalent Ca(1)Mg10Sb2 cuboctahedra, faces with two equivalent Mg(2)Ca2Mg10 cuboctahedra, faces with two equivalent Mg(4)Mg10Sb2 cuboctahedra, and faces with six equivalent Sb(1)Ca2Mg10 cuboctahedra. In the third Mg site, Mg(3) is bonded in a 4-coordinate geometry to two equivalent Ca(1), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), and two equivalent Sb(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 Sb(1) atoms to form distorted MgMg10Sb2 cuboctahedra that share corners with four equivalent Sb(1)Ca2Mg10 cuboctahedra, corners with six equivalent Mg(4)Mg10Sb2 cuboctahedra, edges with two equivalent Sb(1)Ca2Mg10 cuboctahedra, edges with four equivalent Mg(2)Ca2Mg10 cuboctahedra, faces with two equivalent Mg(2)Ca2Mg10 cuboctahedra, faces with two equivalent Mg(4)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Ca2Mg10 cuboctahedra, and faces with six equivalent Ca(1)Mg10Sb2 cuboctahedra. Sb(1) is bonded to two equivalent Ca(1), two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(3) atoms to form SbCa2Mg10 cuboctahedra that share corners with four equivalent Mg(4)Mg10Sb2 cuboctahedra, corners with six equivalent Sb(1)Ca2Mg10 cuboctahedra, edges with two equivalent Mg(4)Mg10Sb2 cuboctahedra, edges with four equivalent Ca(1)Mg10Sb2 cuboctahedra, faces with two equivalent Ca(1)Mg10Sb2 cuboctahedra, faces with two equivalent Mg(4)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Ca2Mg10 cuboctahedra, and faces with six equivalent Mg(2)Ca2Mg10 cuboctahedra.
CaMg6Sb crystallizes in the orthorhombic Amm2 space group. Ca(1) is bonded to two equivalent Mg(2), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Sb(1) atoms to form CaMg10Sb2 cuboctahedra that share corners with four equivalent Mg(2)Ca2Mg10 cuboctahedra, corners with six equivalent Ca(1)Mg10Sb2 cuboctahedra, edges with two equivalent Mg(2)Ca2Mg10 cuboctahedra, edges with four equivalent Sb(1)Ca2Mg10 cuboctahedra, faces with two equivalent Ca(1)Mg10Sb2 cuboctahedra, faces with two equivalent Mg(2)Ca2Mg10 cuboctahedra, faces with two equivalent Sb(1)Ca2Mg10 cuboctahedra, and faces with six equivalent Mg(4)Mg10Sb2 cuboctahedra. Both Ca(1)-Mg(2) bond lengths are 3.37 Å. There are two shorter (3.29 Å) and two longer (3.30 Å) Ca(1)-Mg(1) bond lengths. All Ca(1)-Mg(3) bond lengths are 3.31 Å. Both Ca(1)-Sb(1) bond lengths are 3.20 Å. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 12-coordinate geometry to two equivalent Ca(1), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), and two equivalent Sb(1) atoms. There is one shorter (3.31 Å) and one longer (3.43 Å) Mg(1)-Mg(1) bond length. There is one shorter (3.25 Å) and one longer (3.34 Å) Mg(1)-Mg(2) bond length. Both Mg(1)-Mg(3) bond lengths are 3.17 Å. Both Mg(1)-Mg(4) bond lengths are 3.24 Å. Both Mg(1)-Sb(1) bond lengths are 3.26 Å. In the second Mg site, Mg(2) is bonded to two equivalent Ca(1), two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(3) atoms to form MgCa2Mg10 cuboctahedra that share corners with four equivalent Ca(1)Mg10Sb2 cuboctahedra, corners with six equivalent Mg(2)Ca2Mg10 cuboctahedra, edges with two equivalent Ca(1)Mg10Sb2 cuboctahedra, edges with four equivalent Mg(4)Mg10Sb2 cuboctahedra, faces with two equivalent Ca(1)Mg10Sb2 cuboctahedra, faces with two equivalent Mg(2)Ca2Mg10 cuboctahedra, faces with two equivalent Mg(4)Mg10Sb2 cuboctahedra, and faces with six equivalent Sb(1)Ca2Mg10 cuboctahedra. Both Mg(2)-Mg(4) bond lengths are 3.23 Å. All Mg(2)-Mg(3) bond lengths are 3.20 Å. In the third Mg site, Mg(3) is bonded in a 4-coordinate geometry to two equivalent Ca(1), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), and two equivalent Sb(1) atoms. There is one shorter (3.28 Å) and one longer (3.31 Å) Mg(3)-Mg(4) bond length. There is one shorter (3.20 Å) and one longer (3.39 Å) Mg(3)-Sb(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 Sb(1) atoms to form distorted MgMg10Sb2 cuboctahedra that share corners with four equivalent Sb(1)Ca2Mg10 cuboctahedra, corners with six equivalent Mg(4)Mg10Sb2 cuboctahedra, edges with two equivalent Sb(1)Ca2Mg10 cuboctahedra, edges with four equivalent Mg(2)Ca2Mg10 cuboctahedra, faces with two equivalent Mg(2)Ca2Mg10 cuboctahedra, faces with two equivalent Mg(4)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Ca2Mg10 cuboctahedra, and faces with six equivalent Ca(1)Mg10Sb2 cuboctahedra. Both Mg(4)-Sb(1) bond lengths are 3.37 Å. Sb(1) is bonded to two equivalent Ca(1), two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(3) atoms to form SbCa2Mg10 cuboctahedra that share corners with four equivalent Mg(4)Mg10Sb2 cuboctahedra, corners with six equivalent Sb(1)Ca2Mg10 cuboctahedra, edges with two equivalent Mg(4)Mg10Sb2 cuboctahedra, edges with four equivalent Ca(1)Mg10Sb2 cuboctahedra, faces with two equivalent Ca(1)Mg10Sb2 cuboctahedra, faces with two equivalent Mg(4)Mg10Sb2 cuboctahedra, faces with two equivalent Sb(1)Ca2Mg10 cuboctahedra, and faces with six equivalent Mg(2)Ca2Mg10 cuboctahedra.