RbMg14Sb crystallizes in the hexagonal P-6m2 space group. Rb(1) is bonded to six equivalent Mg(1) and six equivalent Mg(3) atoms to form RbMg12 cuboctahedra that share corners with six equivalent Rb(1)Mg12 cuboctahedra, corners with twelve equivalent Mg(2)Mg10Sb2 cuboctahedra, edges with six equivalent Mg(1)Rb2Mg10 cuboctahedra, edges with twelve equivalent Mg(3)RbMg10Sb cuboctahedra, faces with two equivalent Sb(1)Mg12 cuboctahedra, faces with six equivalent Mg(4)Mg12 cuboctahedra, faces with six equivalent Mg(1)Rb2Mg10 cuboctahedra, and faces with six equivalent Mg(3)RbMg10Sb cuboctahedra. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Rb(1), two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(3) atoms to form distorted MgRb2Mg10 cuboctahedra that share corners with four equivalent Sb(1)Mg12 cuboctahedra, corners with six equivalent Mg(1)Rb2Mg10 cuboctahedra, corners with eight equivalent Mg(2)Mg10Sb2 cuboctahedra, edges with two equivalent Rb(1)Mg12 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(1)Rb2Mg10 cuboctahedra, edges with eight equivalent Mg(3)RbMg10Sb cuboctahedra, faces with two equivalent Rb(1)Mg12 cuboctahedra, faces with two equivalent Mg(2)Mg10Sb2 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with four equivalent Mg(1)Rb2Mg10 cuboctahedra, and faces with ten equivalent Mg(3)RbMg10Sb cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(4), four equivalent Mg(2), four equivalent Mg(3), and two equivalent Sb(1) atoms to form distorted MgMg10Sb2 cuboctahedra that share corners with four equivalent Rb(1)Mg12 cuboctahedra, corners with six equivalent Mg(2)Mg10Sb2 cuboctahedra, corners with eight equivalent Mg(1)Rb2Mg10 cuboctahedra, edges with two equivalent Sb(1)Mg12 cuboctahedra, edges with four equivalent Mg(2)Mg10Sb2 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with eight equivalent Mg(3)RbMg10Sb cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Mg(1)Rb2Mg10 cuboctahedra, faces with two equivalent Sb(1)Mg12 cuboctahedra, faces with four equivalent Mg(2)Mg10Sb2 cuboctahedra, and faces with ten equivalent Mg(3)RbMg10Sb cuboctahedra. In the third Mg site, Mg(3) is bonded to one Rb(1), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), four equivalent Mg(3), and one Sb(1) atom to form distorted MgRbMg10Sb cuboctahedra that share corners with four equivalent Mg(4)Mg12 cuboctahedra, corners with fourteen equivalent Mg(3)RbMg10Sb cuboctahedra, edges with two equivalent Rb(1)Mg12 cuboctahedra, edges with two equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Sb(1)Mg12 cuboctahedra, edges with four equivalent Mg(2)Mg10Sb2 cuboctahedra, edges with four equivalent Mg(1)Rb2Mg10 cuboctahedra, edges with four equivalent Mg(3)RbMg10Sb cuboctahedra,  a faceface with one Rb(1)Mg12 cuboctahedra,  a faceface with one Sb(1)Mg12 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with five equivalent Mg(2)Mg10Sb2 cuboctahedra, faces with five equivalent Mg(1)Rb2Mg10 cuboctahedra, and faces with six equivalent Mg(3)RbMg10Sb cuboctahedra. In the fourth Mg site, Mg(4) is bonded to three equivalent Mg(1), three equivalent Mg(2), and six equivalent Mg(3) atoms to form MgMg12 cuboctahedra that share corners with six equivalent Mg(4)Mg12 cuboctahedra, corners with twelve equivalent Mg(3)RbMg10Sb cuboctahedra, edges with six equivalent Mg(2)Mg10Sb2 cuboctahedra, edges with six equivalent Mg(1)Rb2Mg10 cuboctahedra, edges with six equivalent Mg(3)RbMg10Sb cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with three equivalent Rb(1)Mg12 cuboctahedra, faces with three equivalent Mg(2)Mg10Sb2 cuboctahedra, faces with three equivalent Mg(1)Rb2Mg10 cuboctahedra, faces with three equivalent Sb(1)Mg12 cuboctahedra, and faces with six equivalent Mg(3)RbMg10Sb cuboctahedra. Sb(1) is bonded to six equivalent Mg(2) and six equivalent Mg(3) atoms to form SbMg12 cuboctahedra that share corners with six equivalent Sb(1)Mg12 cuboctahedra, corners with twelve equivalent Mg(1)Rb2Mg10 cuboctahedra, edges with six equivalent Mg(2)Mg10Sb2 cuboctahedra, edges with twelve equivalent Mg(3)RbMg10Sb cuboctahedra, faces with two equivalent Rb(1)Mg12 cuboctahedra, faces with six equivalent Mg(2)Mg10Sb2 cuboctahedra, faces with six equivalent Mg(4)Mg12 cuboctahedra, and faces with six equivalent Mg(3)RbMg10Sb cuboctahedra.
RbMg14Sb crystallizes in the hexagonal P-6m2 space group. Rb(1) is bonded to six equivalent Mg(1) and six equivalent Mg(3) atoms to form RbMg12 cuboctahedra that share corners with six equivalent Rb(1)Mg12 cuboctahedra, corners with twelve equivalent Mg(2)Mg10Sb2 cuboctahedra, edges with six equivalent Mg(1)Rb2Mg10 cuboctahedra, edges with twelve equivalent Mg(3)RbMg10Sb cuboctahedra, faces with two equivalent Sb(1)Mg12 cuboctahedra, faces with six equivalent Mg(4)Mg12 cuboctahedra, faces with six equivalent Mg(1)Rb2Mg10 cuboctahedra, and faces with six equivalent Mg(3)RbMg10Sb cuboctahedra. All Rb(1)-Mg(1) bond lengths are 3.26 Å. All Rb(1)-Mg(3) bond lengths are 3.43 Å. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Rb(1), two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(3) atoms to form distorted MgRb2Mg10 cuboctahedra that share corners with four equivalent Sb(1)Mg12 cuboctahedra, corners with six equivalent Mg(1)Rb2Mg10 cuboctahedra, corners with eight equivalent Mg(2)Mg10Sb2 cuboctahedra, edges with two equivalent Rb(1)Mg12 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(1)Rb2Mg10 cuboctahedra, edges with eight equivalent Mg(3)RbMg10Sb cuboctahedra, faces with two equivalent Rb(1)Mg12 cuboctahedra, faces with two equivalent Mg(2)Mg10Sb2 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with four equivalent Mg(1)Rb2Mg10 cuboctahedra, and faces with ten equivalent Mg(3)RbMg10Sb cuboctahedra. Both Mg(1)-Mg(4) bond lengths are 3.25 Å. There are two shorter (3.16 Å) and two longer (3.36 Å) Mg(1)-Mg(1) bond lengths. All Mg(1)-Mg(3) bond lengths are 3.36 Å. In the second Mg site, Mg(2) is bonded to two equivalent Mg(4), four equivalent Mg(2), four equivalent Mg(3), and two equivalent Sb(1) atoms to form distorted MgMg10Sb2 cuboctahedra that share corners with four equivalent Rb(1)Mg12 cuboctahedra, corners with six equivalent Mg(2)Mg10Sb2 cuboctahedra, corners with eight equivalent Mg(1)Rb2Mg10 cuboctahedra, edges with two equivalent Sb(1)Mg12 cuboctahedra, edges with four equivalent Mg(2)Mg10Sb2 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with eight equivalent Mg(3)RbMg10Sb cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Mg(1)Rb2Mg10 cuboctahedra, faces with two equivalent Sb(1)Mg12 cuboctahedra, faces with four equivalent Mg(2)Mg10Sb2 cuboctahedra, and faces with ten equivalent Mg(3)RbMg10Sb cuboctahedra. Both Mg(2)-Mg(4) bond lengths are 3.30 Å. There are two shorter (3.19 Å) and two longer (3.34 Å) Mg(2)-Mg(2) bond lengths. All Mg(2)-Mg(3) bond lengths are 3.14 Å. Both Mg(2)-Sb(1) bond lengths are 3.26 Å. In the third Mg site, Mg(3) is bonded to one Rb(1), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), four equivalent Mg(3), and one Sb(1) atom to form distorted MgRbMg10Sb cuboctahedra that share corners with four equivalent Mg(4)Mg12 cuboctahedra, corners with fourteen equivalent Mg(3)RbMg10Sb cuboctahedra, edges with two equivalent Rb(1)Mg12 cuboctahedra, edges with two equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Sb(1)Mg12 cuboctahedra, edges with four equivalent Mg(2)Mg10Sb2 cuboctahedra, edges with four equivalent Mg(1)Rb2Mg10 cuboctahedra, edges with four equivalent Mg(3)RbMg10Sb cuboctahedra,  a faceface with one Rb(1)Mg12 cuboctahedra,  a faceface with one Sb(1)Mg12 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with five equivalent Mg(2)Mg10Sb2 cuboctahedra, faces with five equivalent Mg(1)Rb2Mg10 cuboctahedra, and faces with six equivalent Mg(3)RbMg10Sb cuboctahedra. Both Mg(3)-Mg(4) bond lengths are 3.27 Å. There are two shorter (3.15 Å) and two longer (3.37 Å) Mg(3)-Mg(3) bond lengths. The Mg(3)-Sb(1) bond length is 3.18 Å. In the fourth Mg site, Mg(4) is bonded to three equivalent Mg(1), three equivalent Mg(2), and six equivalent Mg(3) atoms to form MgMg12 cuboctahedra that share corners with six equivalent Mg(4)Mg12 cuboctahedra, corners with twelve equivalent Mg(3)RbMg10Sb cuboctahedra, edges with six equivalent Mg(2)Mg10Sb2 cuboctahedra, edges with six equivalent Mg(1)Rb2Mg10 cuboctahedra, edges with six equivalent Mg(3)RbMg10Sb cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with three equivalent Rb(1)Mg12 cuboctahedra, faces with three equivalent Mg(2)Mg10Sb2 cuboctahedra, faces with three equivalent Mg(1)Rb2Mg10 cuboctahedra, faces with three equivalent Sb(1)Mg12 cuboctahedra, and faces with six equivalent Mg(3)RbMg10Sb cuboctahedra. Sb(1) is bonded to six equivalent Mg(2) and six equivalent Mg(3) atoms to form SbMg12 cuboctahedra that share corners with six equivalent Sb(1)Mg12 cuboctahedra, corners with twelve equivalent Mg(1)Rb2Mg10 cuboctahedra, edges with six equivalent Mg(2)Mg10Sb2 cuboctahedra, edges with twelve equivalent Mg(3)RbMg10Sb cuboctahedra, faces with two equivalent Rb(1)Mg12 cuboctahedra, faces with six equivalent Mg(2)Mg10Sb2 cuboctahedra, faces with six equivalent Mg(4)Mg12 cuboctahedra, and faces with six equivalent Mg(3)RbMg10Sb cuboctahedra.