MgCa crystallizes in the hexagonal P-6m2 space group. Ca(1) is bonded to six equivalent Ca(1) and six equivalent Mg(1) atoms to form a mixture of distorted corner, edge, and face-sharing CaCa6Mg6 cuboctahedra. Mg(1) is bonded in a 6-coordinate geometry to six equivalent Ca(1) atoms.
MgCa crystallizes in the hexagonal P-6m2 space group. Ca(1) is bonded to six equivalent Ca(1) and six equivalent Mg(1) atoms to form a mixture of distorted corner, edge, and face-sharing CaCa6Mg6 cuboctahedra. All Ca(1)-Ca(1) bond lengths are 3.67 Å. All Ca(1)-Mg(1) bond lengths are 3.52 Å. Mg(1) is bonded in a 6-coordinate geometry to six equivalent Ca(1) atoms.