RbMg6C crystallizes in the orthorhombic Amm2 space group. Rb(1) is bonded in a 8-coordinate geometry to two equivalent Rb(1), two equivalent Mg(3), and four equivalent Mg(2) atoms. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a single-bond geometry to two equivalent Mg(3), two equivalent Mg(4), and one C(1) atom. In the second Mg site, Mg(2) is bonded in a water-like geometry to two equivalent Rb(1) and two equivalent C(1) atoms. In the third Mg site, Mg(3) 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. In the fourth Mg site, Mg(4) is bonded in a 8-coordinate geometry to two equivalent Mg(3), two equivalent Mg(4), and four equivalent Mg(1) atoms. C(1) is bonded to two equivalent Mg(1) and four equivalent Mg(2) atoms to form distorted edge-sharing CMg6 pentagonal pyramids.
RbMg6C crystallizes in the orthorhombic Amm2 space group. Rb(1) is bonded in a 8-coordinate geometry to two equivalent Rb(1), two equivalent Mg(3), and four equivalent Mg(2) atoms. Both Rb(1)-Rb(1) bond lengths are 3.42 Å. Both Rb(1)-Mg(3) bond lengths are 3.71 Å. All Rb(1)-Mg(2) bond lengths are 4.05 Å. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a single-bond geometry to two equivalent Mg(3), two equivalent Mg(4), and one C(1) atom. Both Mg(1)-Mg(3) bond lengths are 3.11 Å. Both Mg(1)-Mg(4) bond lengths are 3.40 Å. The Mg(1)-C(1) bond length is 2.33 Å. In the second Mg site, Mg(2) is bonded in a water-like geometry to two equivalent Rb(1) and two equivalent C(1) atoms. Both Mg(2)-C(1) bond lengths are 2.28 Å. In the third Mg site, Mg(3) 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. Both Mg(3)-Mg(3) bond lengths are 3.42 Å. Both Mg(3)-Mg(4) bond lengths are 2.93 Å. In the fourth Mg site, Mg(4) is bonded in a 8-coordinate geometry to two equivalent Mg(3), two equivalent Mg(4), and four equivalent Mg(1) atoms. Both Mg(4)-Mg(4) bond lengths are 3.42 Å. C(1) is bonded to two equivalent Mg(1) and four equivalent Mg(2) atoms to form distorted edge-sharing CMg6 pentagonal pyramids.