Ca2Mg crystallizes in the hexagonal P-62m space group. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent Ca(2); six Ca(1,1); and four equivalent Mg(1) atoms to form distorted CaCa8Mg4 cuboctahedra that share corners with eighteen Ca(1,1)Ca8Mg4 cuboctahedra; edges with four equivalent Ca(2)Ca6Mg6 cuboctahedra; edges with six equivalent Ca(1)Ca8Mg4 cuboctahedra; faces with four equivalent Ca(2)Ca6Mg6 cuboctahedra; and faces with eight Ca(1,1)Ca8Mg4 cuboctahedra. In the second Ca site, Ca(1) is bonded to two equivalent Ca(2), six equivalent Ca(1), and four equivalent Mg(1) atoms to form distorted CaCa8Mg4 cuboctahedra that share corners with eighteen equivalent Ca(1)Ca8Mg4 cuboctahedra; edges with four equivalent Ca(2)Ca6Mg6 cuboctahedra; edges with six equivalent Ca(1)Ca8Mg4 cuboctahedra; faces with four equivalent Ca(2)Ca6Mg6 cuboctahedra; and faces with eight Ca(1,1)Ca8Mg4 cuboctahedra. In the third Ca site, Ca(2) is bonded to six Ca(1,1) and six equivalent Mg(1) atoms to form CaCa6Mg6 cuboctahedra that share edges with six equivalent Ca(2)Ca6Mg6 cuboctahedra; edges with twelve Ca(1,1)Ca8Mg4 cuboctahedra; faces with two equivalent Ca(2)Ca6Mg6 cuboctahedra; and faces with twelve Ca(1,1)Ca8Mg4 cuboctahedra. Mg(1) is bonded in a 9-coordinate geometry to three equivalent Ca(2) and six Ca(1,1) atoms.
Ca2Mg crystallizes in the hexagonal P-62m space group. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent Ca(2); six Ca(1,1); and four equivalent Mg(1) atoms to form distorted CaCa8Mg4 cuboctahedra that share corners with eighteen Ca(1,1)Ca8Mg4 cuboctahedra; edges with four equivalent Ca(2)Ca6Mg6 cuboctahedra; edges with six equivalent Ca(1)Ca8Mg4 cuboctahedra; faces with four equivalent Ca(2)Ca6Mg6 cuboctahedra; and faces with eight Ca(1,1)Ca8Mg4 cuboctahedra. Both Ca(1)-Ca(2) bond lengths are 3.71 Å. There are four shorter (3.61 Å) and two longer (3.83 Å) Ca(1)-Ca(1,1) bond lengths. All Ca(1)-Mg(1) bond lengths are 3.64 Å. In the second Ca site, Ca(1) is bonded to two equivalent Ca(2), six equivalent Ca(1), and four equivalent Mg(1) atoms to form distorted CaCa8Mg4 cuboctahedra that share corners with eighteen equivalent Ca(1)Ca8Mg4 cuboctahedra; edges with four equivalent Ca(2)Ca6Mg6 cuboctahedra; edges with six equivalent Ca(1)Ca8Mg4 cuboctahedra; faces with four equivalent Ca(2)Ca6Mg6 cuboctahedra; and faces with eight Ca(1,1)Ca8Mg4 cuboctahedra. Both Ca(1)-Ca(2) bond lengths are 3.71 Å. All Ca(1)-Mg(1) bond lengths are 3.64 Å. In the third Ca site, Ca(2) is bonded to six Ca(1,1) and six equivalent Mg(1) atoms to form CaCa6Mg6 cuboctahedra that share edges with six equivalent Ca(2)Ca6Mg6 cuboctahedra; edges with twelve Ca(1,1)Ca8Mg4 cuboctahedra; faces with two equivalent Ca(2)Ca6Mg6 cuboctahedra; and faces with twelve Ca(1,1)Ca8Mg4 cuboctahedra. All Ca(2)-Mg(1) bond lengths are 3.68 Å. Mg(1) is bonded in a 9-coordinate geometry to three equivalent Ca(2) and six Ca(1,1) atoms.