Ca2Mg crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent Ca(1), two equivalent Ca(2), two equivalent Ca(3), four equivalent Ca(4), and two equivalent Mg(1) atoms to form distorted CaCa10Mg2 cuboctahedra that share corners with six equivalent Ca(1)Ca10Mg2 cuboctahedra, corners with six equivalent Ca(3)Ca6Mg6 cuboctahedra, corners with six equivalent Ca(2)Ca8Mg4 cuboctahedra, edges with three equivalent Ca(3)Ca6Mg6 cuboctahedra, edges with three equivalent Ca(2)Ca8Mg4 cuboctahedra, edges with four equivalent Ca(4)Ca8Mg4 cuboctahedra, faces with two equivalent Ca(3)Ca6Mg6 cuboctahedra, faces with two equivalent Ca(2)Ca8Mg4 cuboctahedra, faces with four equivalent Ca(1)Ca10Mg2 cuboctahedra, and faces with four equivalent Ca(4)Ca8Mg4 cuboctahedra. In the second Ca site, Ca(2) is bonded to two equivalent Ca(1), two equivalent Ca(2), two equivalent Ca(3), two equivalent Ca(4), and four equivalent Mg(2) atoms to form distorted CaCa8Mg4 cuboctahedra that share corners with six equivalent Ca(1)Ca10Mg2 cuboctahedra, corners with six equivalent Ca(3)Ca6Mg6 cuboctahedra, corners with six equivalent Ca(2)Ca8Mg4 cuboctahedra, edges with three equivalent Ca(1)Ca10Mg2 cuboctahedra, edges with three equivalent Ca(3)Ca6Mg6 cuboctahedra, faces with two equivalent Ca(1)Ca10Mg2 cuboctahedra, faces with two equivalent Ca(3)Ca6Mg6 cuboctahedra, faces with four equivalent Ca(2)Ca8Mg4 cuboctahedra, and faces with six equivalent Ca(4)Ca8Mg4 cuboctahedra. In the third Ca site, Ca(3) is bonded to two equivalent Ca(1), two equivalent Ca(2), two equivalent Ca(3), two equivalent Mg(2), and four equivalent Mg(1) atoms to form distorted CaCa6Mg6 cuboctahedra that share corners with six equivalent Ca(1)Ca10Mg2 cuboctahedra, corners with six equivalent Ca(3)Ca6Mg6 cuboctahedra, corners with six equivalent Ca(2)Ca8Mg4 cuboctahedra, edges with three equivalent Ca(1)Ca10Mg2 cuboctahedra, edges with three equivalent Ca(2)Ca8Mg4 cuboctahedra, edges with eight equivalent Ca(4)Ca8Mg4 cuboctahedra, faces with two equivalent Ca(1)Ca10Mg2 cuboctahedra, faces with two equivalent Ca(2)Ca8Mg4 cuboctahedra, faces with two equivalent Ca(4)Ca8Mg4 cuboctahedra, and faces with four equivalent Ca(3)Ca6Mg6 cuboctahedra. In the fourth Ca site, Ca(4) is bonded to two equivalent Ca(2), two equivalent Ca(4), four equivalent Ca(1), two equivalent Mg(1), and two equivalent Mg(2) atoms to form CaCa8Mg4 cuboctahedra that share corners with six equivalent Ca(4)Ca8Mg4 cuboctahedra, edges with four equivalent Ca(1)Ca10Mg2 cuboctahedra, edges with eight equivalent Ca(3)Ca6Mg6 cuboctahedra, faces with two equivalent Ca(3)Ca6Mg6 cuboctahedra, faces with four equivalent Ca(1)Ca10Mg2 cuboctahedra, faces with four equivalent Ca(4)Ca8Mg4 cuboctahedra, and faces with six equivalent Ca(2)Ca8Mg4 cuboctahedra. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 8-coordinate geometry to two equivalent Ca(1), two equivalent Ca(4), and four equivalent Ca(3) atoms. In the second Mg site, Mg(2) is bonded in a 8-coordinate geometry to two equivalent Ca(3), two equivalent Ca(4), and four equivalent Ca(2) atoms.
Ca2Mg crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent Ca(1), two equivalent Ca(2), two equivalent Ca(3), four equivalent Ca(4), and two equivalent Mg(1) atoms to form distorted CaCa10Mg2 cuboctahedra that share corners with six equivalent Ca(1)Ca10Mg2 cuboctahedra, corners with six equivalent Ca(3)Ca6Mg6 cuboctahedra, corners with six equivalent Ca(2)Ca8Mg4 cuboctahedra, edges with three equivalent Ca(3)Ca6Mg6 cuboctahedra, edges with three equivalent Ca(2)Ca8Mg4 cuboctahedra, edges with four equivalent Ca(4)Ca8Mg4 cuboctahedra, faces with two equivalent Ca(3)Ca6Mg6 cuboctahedra, faces with two equivalent Ca(2)Ca8Mg4 cuboctahedra, faces with four equivalent Ca(1)Ca10Mg2 cuboctahedra, and faces with four equivalent Ca(4)Ca8Mg4 cuboctahedra. Both Ca(1)-Ca(1) bond lengths are 3.77 Å. Both Ca(1)-Ca(2) bond lengths are 3.80 Å. Both Ca(1)-Ca(3) bond lengths are 3.66 Å. All Ca(1)-Ca(4) bond lengths are 3.66 Å. Both Ca(1)-Mg(1) bond lengths are 3.62 Å. In the second Ca site, Ca(2) is bonded to two equivalent Ca(1), two equivalent Ca(2), two equivalent Ca(3), two equivalent Ca(4), and four equivalent Mg(2) atoms to form distorted CaCa8Mg4 cuboctahedra that share corners with six equivalent Ca(1)Ca10Mg2 cuboctahedra, corners with six equivalent Ca(3)Ca6Mg6 cuboctahedra, corners with six equivalent Ca(2)Ca8Mg4 cuboctahedra, edges with three equivalent Ca(1)Ca10Mg2 cuboctahedra, edges with three equivalent Ca(3)Ca6Mg6 cuboctahedra, faces with two equivalent Ca(1)Ca10Mg2 cuboctahedra, faces with two equivalent Ca(3)Ca6Mg6 cuboctahedra, faces with four equivalent Ca(2)Ca8Mg4 cuboctahedra, and faces with six equivalent Ca(4)Ca8Mg4 cuboctahedra. Both Ca(2)-Ca(2) bond lengths are 3.77 Å. Both Ca(2)-Ca(3) bond lengths are 3.69 Å. Both Ca(2)-Ca(4) bond lengths are 3.67 Å. All Ca(2)-Mg(2) bond lengths are 3.64 Å. In the third Ca site, Ca(3) is bonded to two equivalent Ca(1), two equivalent Ca(2), two equivalent Ca(3), two equivalent Mg(2), and four equivalent Mg(1) atoms to form distorted CaCa6Mg6 cuboctahedra that share corners with six equivalent Ca(1)Ca10Mg2 cuboctahedra, corners with six equivalent Ca(3)Ca6Mg6 cuboctahedra, corners with six equivalent Ca(2)Ca8Mg4 cuboctahedra, edges with three equivalent Ca(1)Ca10Mg2 cuboctahedra, edges with three equivalent Ca(2)Ca8Mg4 cuboctahedra, edges with eight equivalent Ca(4)Ca8Mg4 cuboctahedra, faces with two equivalent Ca(1)Ca10Mg2 cuboctahedra, faces with two equivalent Ca(2)Ca8Mg4 cuboctahedra, faces with two equivalent Ca(4)Ca8Mg4 cuboctahedra, and faces with four equivalent Ca(3)Ca6Mg6 cuboctahedra. Both Ca(3)-Ca(3) bond lengths are 3.77 Å. Both Ca(3)-Mg(2) bond lengths are 3.64 Å. All Ca(3)-Mg(1) bond lengths are 3.64 Å. In the fourth Ca site, Ca(4) is bonded to two equivalent Ca(2), two equivalent Ca(4), four equivalent Ca(1), two equivalent Mg(1), and two equivalent Mg(2) atoms to form CaCa8Mg4 cuboctahedra that share corners with six equivalent Ca(4)Ca8Mg4 cuboctahedra, edges with four equivalent Ca(1)Ca10Mg2 cuboctahedra, edges with eight equivalent Ca(3)Ca6Mg6 cuboctahedra, faces with two equivalent Ca(3)Ca6Mg6 cuboctahedra, faces with four equivalent Ca(1)Ca10Mg2 cuboctahedra, faces with four equivalent Ca(4)Ca8Mg4 cuboctahedra, and faces with six equivalent Ca(2)Ca8Mg4 cuboctahedra. Both Ca(4)-Ca(4) bond lengths are 3.77 Å. Both Ca(4)-Mg(1) bond lengths are 3.73 Å. Both Ca(4)-Mg(2) bond lengths are 3.73 Å. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 8-coordinate geometry to two equivalent Ca(1), two equivalent Ca(4), and four equivalent Ca(3) atoms. In the second Mg site, Mg(2) is bonded in a 8-coordinate geometry to two equivalent Ca(3), two equivalent Ca(4), and four equivalent Ca(2) atoms.