CaMg7 crystallizes in the hexagonal P-6m2 space group. Ca(1) is bonded to six Mg(1,1) and six Mg(2,2) atoms to form CaMg12 cuboctahedra that share corners with six equivalent Ca(1)Mg12 cuboctahedra; corners with twelve Mg(1,1)Ca2Mg10 cuboctahedra; edges with six Mg(1,1)Ca2Mg10 cuboctahedra; edges with twelve Mg(2,2)Ca2Mg10 cuboctahedra; faces with two equivalent Ca(1)Mg12 cuboctahedra; faces with six Mg(1,1)Ca2Mg10 cuboctahedra; faces with six Mg(2,2)Ca2Mg10 cuboctahedra; and faces with six equivalent Mg(3)Mg12 cuboctahedra. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Ca(1), two equivalent Mg(3), four equivalent Mg(1), and four equivalent Mg(2) atoms to form distorted MgCa2Mg10 cuboctahedra that share corners with four equivalent Ca(1)Mg12 cuboctahedra; corners with fourteen Mg(1,1)Ca2Mg10 cuboctahedra; edges with two equivalent Ca(1)Mg12 cuboctahedra; edges with four equivalent Mg(1)Ca2Mg10 cuboctahedra; edges with four equivalent Mg(3)Mg12 cuboctahedra; edges with eight equivalent Mg(2)Ca2Mg10 cuboctahedra; faces with two equivalent Ca(1)Mg12 cuboctahedra; faces with two equivalent Mg(3)Mg12 cuboctahedra; faces with six Mg(1,1)Ca2Mg10 cuboctahedra; and faces with ten Mg(2,2)Ca2Mg10 cuboctahedra. In the second Mg site, Mg(1) is bonded to two equivalent Ca(1); two equivalent Mg(3); four Mg(1,1); and four Mg(2,2) atoms to form distorted MgCa2Mg10 cuboctahedra that share corners with four equivalent Ca(1)Mg12 cuboctahedra; corners with fourteen Mg(1,1)Ca2Mg10 cuboctahedra; edges with two equivalent Ca(1)Mg12 cuboctahedra; edges with four Mg(1,1)Ca2Mg10 cuboctahedra; edges with four equivalent Mg(3)Mg12 cuboctahedra; edges with eight Mg(2,2)Ca2Mg10 cuboctahedra; faces with two equivalent Ca(1)Mg12 cuboctahedra; faces with two equivalent Mg(3)Mg12 cuboctahedra; faces with six Mg(1,1)Ca2Mg10 cuboctahedra; and faces with ten Mg(2,2)Ca2Mg10 cuboctahedra. In the third Mg site, Mg(2) is bonded to two equivalent Ca(1); two equivalent Mg(3); four Mg(1,1); and four Mg(2,2) atoms to form distorted MgCa2Mg10 cuboctahedra that share corners with four equivalent Mg(3)Mg12 cuboctahedra; corners with fourteen Mg(2,2)Ca2Mg10 cuboctahedra; edges with two equivalent Mg(3)Mg12 cuboctahedra; edges with four equivalent Ca(1)Mg12 cuboctahedra; edges with four Mg(2,2)Ca2Mg10 cuboctahedra; edges with eight Mg(1,1)Ca2Mg10 cuboctahedra; faces with two equivalent Ca(1)Mg12 cuboctahedra; faces with two equivalent Mg(3)Mg12 cuboctahedra; faces with six Mg(2,2)Ca2Mg10 cuboctahedra; and faces with ten Mg(1,1)Ca2Mg10 cuboctahedra. In the fourth Mg site, Mg(2) is bonded to two equivalent Ca(1), two equivalent Mg(3), four equivalent Mg(1), and four equivalent Mg(2) atoms to form distorted MgCa2Mg10 cuboctahedra that share corners with four equivalent Mg(3)Mg12 cuboctahedra; corners with fourteen Mg(2,2)Ca2Mg10 cuboctahedra; edges with two equivalent Mg(3)Mg12 cuboctahedra; edges with four equivalent Ca(1)Mg12 cuboctahedra; edges with four equivalent Mg(2)Ca2Mg10 cuboctahedra; edges with eight equivalent Mg(1)Ca2Mg10 cuboctahedra; faces with two equivalent Ca(1)Mg12 cuboctahedra; faces with two equivalent Mg(3)Mg12 cuboctahedra; faces with six Mg(2,2)Ca2Mg10 cuboctahedra; and faces with ten Mg(1,1)Ca2Mg10 cuboctahedra. In the fifth Mg site, Mg(3) is bonded to six Mg(1,1) and six Mg(2,2) atoms to form MgMg12 cuboctahedra that share corners with six equivalent Mg(3)Mg12 cuboctahedra; corners with twelve Mg(2,2)Ca2Mg10 cuboctahedra; edges with six Mg(2,2)Ca2Mg10 cuboctahedra; edges with twelve Mg(1,1)Ca2Mg10 cuboctahedra; faces with two equivalent Mg(3)Mg12 cuboctahedra; faces with six equivalent Ca(1)Mg12 cuboctahedra; faces with six Mg(1,1)Ca2Mg10 cuboctahedra; and faces with six Mg(2,2)Ca2Mg10 cuboctahedra.
CaMg7 crystallizes in the hexagonal P-6m2 space group. Ca(1) is bonded to six Mg(1,1) and six Mg(2,2) atoms to form CaMg12 cuboctahedra that share corners with six equivalent Ca(1)Mg12 cuboctahedra; corners with twelve Mg(1,1)Ca2Mg10 cuboctahedra; edges with six Mg(1,1)Ca2Mg10 cuboctahedra; edges with twelve Mg(2,2)Ca2Mg10 cuboctahedra; faces with two equivalent Ca(1)Mg12 cuboctahedra; faces with six Mg(1,1)Ca2Mg10 cuboctahedra; faces with six Mg(2,2)Ca2Mg10 cuboctahedra; and faces with six equivalent Mg(3)Mg12 cuboctahedra. All Ca(1)-Mg(1,1) bond lengths are 3.32 Å. All Ca(1)-Mg(2,2) bond lengths are 3.28 Å. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Ca(1), two equivalent Mg(3), four equivalent Mg(1), and four equivalent Mg(2) atoms to form distorted MgCa2Mg10 cuboctahedra that share corners with four equivalent Ca(1)Mg12 cuboctahedra; corners with fourteen Mg(1,1)Ca2Mg10 cuboctahedra; edges with two equivalent Ca(1)Mg12 cuboctahedra; edges with four equivalent Mg(1)Ca2Mg10 cuboctahedra; edges with four equivalent Mg(3)Mg12 cuboctahedra; edges with eight equivalent Mg(2)Ca2Mg10 cuboctahedra; faces with two equivalent Ca(1)Mg12 cuboctahedra; faces with two equivalent Mg(3)Mg12 cuboctahedra; faces with six Mg(1,1)Ca2Mg10 cuboctahedra; and faces with ten Mg(2,2)Ca2Mg10 cuboctahedra. Both Mg(1)-Mg(3) bond lengths are 3.27 Å. There are two shorter (3.28 Å) and two longer (3.37 Å) Mg(1)-Mg(1) bond lengths. All Mg(1)-Mg(2) bond lengths are 3.24 Å. In the second Mg site, Mg(1) is bonded to two equivalent Ca(1); two equivalent Mg(3); four Mg(1,1); and four Mg(2,2) atoms to form distorted MgCa2Mg10 cuboctahedra that share corners with four equivalent Ca(1)Mg12 cuboctahedra; corners with fourteen Mg(1,1)Ca2Mg10 cuboctahedra; edges with two equivalent Ca(1)Mg12 cuboctahedra; edges with four Mg(1,1)Ca2Mg10 cuboctahedra; edges with four equivalent Mg(3)Mg12 cuboctahedra; edges with eight Mg(2,2)Ca2Mg10 cuboctahedra; faces with two equivalent Ca(1)Mg12 cuboctahedra; faces with two equivalent Mg(3)Mg12 cuboctahedra; faces with six Mg(1,1)Ca2Mg10 cuboctahedra; and faces with ten Mg(2,2)Ca2Mg10 cuboctahedra. Both Mg(1)-Mg(3) bond lengths are 3.27 Å. There is one shorter (3.28 Å) and one longer (3.37 Å) Mg(1)-Mg(1) bond length. All Mg(1)-Mg(2,2) bond lengths are 3.24 Å. In the third Mg site, Mg(2) is bonded to two equivalent Ca(1); two equivalent Mg(3); four Mg(1,1); and four Mg(2,2) atoms to form distorted MgCa2Mg10 cuboctahedra that share corners with four equivalent Mg(3)Mg12 cuboctahedra; corners with fourteen Mg(2,2)Ca2Mg10 cuboctahedra; edges with two equivalent Mg(3)Mg12 cuboctahedra; edges with four equivalent Ca(1)Mg12 cuboctahedra; edges with four Mg(2,2)Ca2Mg10 cuboctahedra; edges with eight Mg(1,1)Ca2Mg10 cuboctahedra; faces with two equivalent Ca(1)Mg12 cuboctahedra; faces with two equivalent Mg(3)Mg12 cuboctahedra; faces with six Mg(2,2)Ca2Mg10 cuboctahedra; and faces with ten Mg(1,1)Ca2Mg10 cuboctahedra. Both Mg(2)-Mg(3) bond lengths are 3.32 Å. There are two shorter (3.25 Å) and two longer (3.39 Å) Mg(2)-Mg(2,2) bond lengths. In the fourth Mg site, Mg(2) is bonded to two equivalent Ca(1), two equivalent Mg(3), four equivalent Mg(1), and four equivalent Mg(2) atoms to form distorted MgCa2Mg10 cuboctahedra that share corners with four equivalent Mg(3)Mg12 cuboctahedra; corners with fourteen Mg(2,2)Ca2Mg10 cuboctahedra; edges with two equivalent Mg(3)Mg12 cuboctahedra; edges with four equivalent Ca(1)Mg12 cuboctahedra; edges with four equivalent Mg(2)Ca2Mg10 cuboctahedra; edges with eight equivalent Mg(1)Ca2Mg10 cuboctahedra; faces with two equivalent Ca(1)Mg12 cuboctahedra; faces with two equivalent Mg(3)Mg12 cuboctahedra; faces with six Mg(2,2)Ca2Mg10 cuboctahedra; and faces with ten Mg(1,1)Ca2Mg10 cuboctahedra. Both Mg(2)-Mg(3) bond lengths are 3.32 Å. In the fifth Mg site, Mg(3) is bonded to six Mg(1,1) and six Mg(2,2) atoms to form MgMg12 cuboctahedra that share corners with six equivalent Mg(3)Mg12 cuboctahedra; corners with twelve Mg(2,2)Ca2Mg10 cuboctahedra; edges with six Mg(2,2)Ca2Mg10 cuboctahedra; edges with twelve Mg(1,1)Ca2Mg10 cuboctahedra; faces with two equivalent Mg(3)Mg12 cuboctahedra; faces with six equivalent Ca(1)Mg12 cuboctahedra; faces with six Mg(1,1)Ca2Mg10 cuboctahedra; and faces with six Mg(2,2)Ca2Mg10 cuboctahedra.