RbMg6Cr crystallizes in the orthorhombic Amm2 space group. Rb(1) is bonded to two equivalent Mg(2), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Cr(1) atoms to form a mixture of face and corner-sharing RbMg10Cr2 cuboctahedra. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 11-coordinate geometry to two equivalent Rb(1), one Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), and two equivalent Cr(1) atoms. In the second Mg site, Mg(2) is bonded in a 12-coordinate geometry to two equivalent Rb(1), two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(3) atoms. In the third Mg site, Mg(3) is bonded in a 3-coordinate geometry to two equivalent Rb(1), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), and one Cr(1) atom. In the fourth Mg site, Mg(4) is bonded in a 12-coordinate geometry to two equivalent Mg(2), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Cr(1) atoms. Cr(1) is bonded in a 10-coordinate geometry to two equivalent Rb(1), two equivalent Mg(3), two equivalent Mg(4), and four equivalent Mg(1) atoms.
RbMg6Cr crystallizes in the orthorhombic Amm2 space group. Rb(1) is bonded to two equivalent Mg(2), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Cr(1) atoms to form a mixture of face and corner-sharing RbMg10Cr2 cuboctahedra. Both Rb(1)-Mg(2) bond lengths are 3.44 Å. There are two shorter (3.37 Å) and two longer (3.52 Å) Rb(1)-Mg(1) bond lengths. All Rb(1)-Mg(3) bond lengths are 3.42 Å. Both Rb(1)-Cr(1) bond lengths are 3.58 Å. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 11-coordinate geometry to two equivalent Rb(1), one Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), and two equivalent Cr(1) atoms. The Mg(1)-Mg(1) bond length is 3.13 Å. There is one shorter (3.43 Å) and one longer (3.46 Å) Mg(1)-Mg(2) bond length. Both Mg(1)-Mg(3) bond lengths are 3.25 Å. Both Mg(1)-Mg(4) bond lengths are 3.35 Å. Both Mg(1)-Cr(1) bond lengths are 3.10 Å. In the second Mg site, Mg(2) is bonded in a 12-coordinate geometry to two equivalent Rb(1), two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(3) atoms. Both Mg(2)-Mg(4) bond lengths are 3.28 Å. All Mg(2)-Mg(3) bond lengths are 3.25 Å. In the third Mg site, Mg(3) is bonded in a 3-coordinate geometry to two equivalent Rb(1), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), and one Cr(1) atom. There is one shorter (3.41 Å) and one longer (3.50 Å) Mg(3)-Mg(4) bond length. The Mg(3)-Cr(1) bond length is 2.90 Å. In the fourth Mg site, Mg(4) is bonded in a 12-coordinate geometry to two equivalent Mg(2), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Cr(1) atoms. Both Mg(4)-Cr(1) bond lengths are 3.46 Å. Cr(1) is bonded in a 10-coordinate geometry to two equivalent Rb(1), two equivalent Mg(3), two equivalent Mg(4), and four equivalent Mg(1) atoms.