RbCaMg6 crystallizes in the orthorhombic Amm2 space group. Rb(1) is bonded to two equivalent Ca(1), two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(2) atoms to form distorted RbCa2Mg10 cuboctahedra that share corners with four equivalent Ca(1)Rb2Mg10 cuboctahedra, corners with six equivalent Rb(1)Ca2Mg10 cuboctahedra, edges with two equivalent Ca(1)Rb2Mg10 cuboctahedra, faces with two equivalent Rb(1)Ca2Mg10 cuboctahedra, and faces with two equivalent Ca(1)Rb2Mg10 cuboctahedra. Ca(1) is bonded to two equivalent Rb(1), two equivalent Mg(3), four equivalent Mg(1), and four equivalent Mg(2) atoms to form distorted CaRb2Mg10 cuboctahedra that share corners with four equivalent Rb(1)Ca2Mg10 cuboctahedra, corners with six equivalent Ca(1)Rb2Mg10 cuboctahedra, edges with two equivalent Rb(1)Ca2Mg10 cuboctahedra, faces with two equivalent Rb(1)Ca2Mg10 cuboctahedra, and faces with two equivalent Ca(1)Rb2Mg10 cuboctahedra. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 10-coordinate geometry to two equivalent Rb(1), two equivalent Ca(1), two equivalent Mg(2), two equivalent Mg(3), and two equivalent Mg(4) atoms. In the second Mg site, Mg(2) is bonded in a 8-coordinate geometry to two equivalent Rb(1), two equivalent Ca(1), one Mg(3), one Mg(4), and two equivalent Mg(1) atoms. In the third Mg site, Mg(3) is bonded in a 8-coordinate geometry to two equivalent Ca(1), two equivalent Mg(2), and four equivalent Mg(1) atoms. In the fourth Mg site, Mg(4) is bonded in a 8-coordinate geometry to two equivalent Rb(1), two equivalent Mg(2), and four equivalent Mg(1) atoms.
RbCaMg6 crystallizes in the orthorhombic Amm2 space group. Rb(1) is bonded to two equivalent Ca(1), two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(2) atoms to form distorted RbCa2Mg10 cuboctahedra that share corners with four equivalent Ca(1)Rb2Mg10 cuboctahedra, corners with six equivalent Rb(1)Ca2Mg10 cuboctahedra, edges with two equivalent Ca(1)Rb2Mg10 cuboctahedra, faces with two equivalent Rb(1)Ca2Mg10 cuboctahedra, and faces with two equivalent Ca(1)Rb2Mg10 cuboctahedra. Both Rb(1)-Ca(1) bond lengths are 3.82 Å. Both Rb(1)-Mg(4) bond lengths are 3.56 Å. There are two shorter (3.44 Å) and two longer (3.51 Å) Rb(1)-Mg(1) bond lengths. All Rb(1)-Mg(2) bond lengths are 3.57 Å. Ca(1) is bonded to two equivalent Rb(1), two equivalent Mg(3), four equivalent Mg(1), and four equivalent Mg(2) atoms to form distorted CaRb2Mg10 cuboctahedra that share corners with four equivalent Rb(1)Ca2Mg10 cuboctahedra, corners with six equivalent Ca(1)Rb2Mg10 cuboctahedra, edges with two equivalent Rb(1)Ca2Mg10 cuboctahedra, faces with two equivalent Rb(1)Ca2Mg10 cuboctahedra, and faces with two equivalent Ca(1)Rb2Mg10 cuboctahedra. Both Ca(1)-Mg(3) bond lengths are 3.52 Å. There are two shorter (3.43 Å) and two longer (3.53 Å) Ca(1)-Mg(1) bond lengths. All Ca(1)-Mg(2) bond lengths are 3.44 Å. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 10-coordinate geometry to two equivalent Rb(1), two equivalent Ca(1), two equivalent Mg(2), two equivalent Mg(3), and two equivalent Mg(4) atoms. Both Mg(1)-Mg(2) bond lengths are 3.31 Å. Both Mg(1)-Mg(3) bond lengths are 3.43 Å. Both Mg(1)-Mg(4) bond lengths are 3.43 Å. In the second Mg site, Mg(2) is bonded in a 8-coordinate geometry to two equivalent Rb(1), two equivalent Ca(1), one Mg(3), one Mg(4), and two equivalent Mg(1) atoms. The Mg(2)-Mg(3) bond length is 3.31 Å. The Mg(2)-Mg(4) bond length is 3.10 Å. In the third Mg site, Mg(3) is bonded in a 8-coordinate geometry to two equivalent Ca(1), two equivalent Mg(2), and four equivalent Mg(1) atoms. In the fourth Mg site, Mg(4) is bonded in a 8-coordinate geometry to two equivalent Rb(1), two equivalent Mg(2), and four equivalent Mg(1) atoms.