RbMg14Cu crystallizes in the orthorhombic Amm2 space group. Rb(1) is bonded to two equivalent Mg(7), four equivalent Mg(3), four equivalent Mg(5), and two equivalent Cu(1) atoms to form RbMg10Cu2 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with six equivalent Rb(1)Mg10Cu2 cuboctahedra, corners with eight equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Cu(1)Rb2Mg10 cuboctahedra, edges with four equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, edges with four equivalent Mg(7)RbMg11 cuboctahedra, edges with eight equivalent Mg(5)RbMg10Cu cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Mg(7)RbMg11 cuboctahedra, faces with two equivalent Cu(1)Rb2Mg10 cuboctahedra, faces with four equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, and faces with four equivalent Mg(5)RbMg10Cu cuboctahedra. There are seven inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(2), two equivalent Mg(6), four equivalent Mg(4), and four equivalent Mg(5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Rb(1)Mg10Cu2 cuboctahedra, corners with six equivalent Mg(1)Mg12 cuboctahedra, corners with eight equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with eight equivalent Mg(5)RbMg10Cu cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Cu(1)Rb2Mg10 cuboctahedra, faces with four equivalent Mg(4)Mg12 cuboctahedra, faces with four equivalent Mg(5)RbMg10Cu cuboctahedra, and faces with six equivalent Mg(7)RbMg11 cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(7), four equivalent Mg(4), and four equivalent Mg(5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Cu(1)Rb2Mg10 cuboctahedra, corners with six equivalent Mg(2)Mg12 cuboctahedra, corners with eight equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(7)RbMg11 cuboctahedra, edges with eight equivalent Mg(5)RbMg10Cu cuboctahedra, faces with two equivalent Rb(1)Mg10Cu2 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Mg(7)RbMg11 cuboctahedra, faces with four equivalent Mg(4)Mg12 cuboctahedra, and faces with four equivalent Mg(5)RbMg10Cu cuboctahedra. In the third Mg site, Mg(3) is bonded to two equivalent Rb(1), two equivalent Mg(3), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), and two equivalent Cu(1) atoms to form distorted MgRb2Mg8Cu2 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with four equivalent Mg(2)Mg12 cuboctahedra, corners with four equivalent Mg(4)Mg12 cuboctahedra, corners with six equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, edges with two equivalent Rb(1)Mg10Cu2 cuboctahedra, edges with two equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, edges with two equivalent Cu(1)Rb2Mg10 cuboctahedra, edges with four equivalent Mg(5)RbMg10Cu cuboctahedra, edges with four equivalent Mg(7)RbMg11 cuboctahedra, faces with two equivalent Rb(1)Mg10Cu2 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, faces with two equivalent Mg(7)RbMg11 cuboctahedra, faces with two equivalent Cu(1)Rb2Mg10 cuboctahedra, and faces with eight equivalent Mg(5)RbMg10Cu cuboctahedra. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), two equivalent Mg(5), two equivalent Mg(6), and two equivalent Mg(7) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Rb(1)Mg10Cu2 cuboctahedra, corners with four equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, corners with four equivalent Cu(1)Rb2Mg10 cuboctahedra, corners with six equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with two equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(5)RbMg10Cu cuboctahedra, edges with four equivalent Mg(7)RbMg11 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, faces with two equivalent Mg(7)RbMg11 cuboctahedra, and faces with eight equivalent Mg(5)RbMg10Cu cuboctahedra. In the fifth Mg site, Mg(5) is bonded to one Rb(1), one Mg(1), one Mg(2), one Mg(3), one Mg(4), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), and one Cu(1) atom to form distorted MgRbMg10Cu cuboctahedra that share corners with four equivalent Mg(7)RbMg11 cuboctahedra, corners with ten equivalent Mg(5)RbMg10Cu cuboctahedra, edges with two equivalent Rb(1)Mg10Cu2 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with two equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, edges with two equivalent Mg(5)RbMg10Cu cuboctahedra, edges with two equivalent Mg(7)RbMg11 cuboctahedra, edges with two equivalent Cu(1)Rb2Mg10 cuboctahedra,  a faceface with one Rb(1)Mg10Cu2 cuboctahedra,  a faceface with one Mg(1)Mg12 cuboctahedra,  a faceface with one Mg(2)Mg12 cuboctahedra,  a faceface with one Cu(1)Rb2Mg10 cuboctahedra, faces with two equivalent Mg(7)RbMg11 cuboctahedra, faces with four equivalent Mg(4)Mg12 cuboctahedra, faces with four equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, and faces with four equivalent Mg(5)RbMg10Cu cuboctahedra. In the sixth Mg site, Mg(6) is bonded in a distorted single-bond geometry to one Mg(1), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(7), four equivalent Mg(5), and one Cu(1) atom. In the seventh Mg site, Mg(7) is bonded to one Rb(1), one Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(6), and four equivalent Mg(5) atoms to form distorted MgRbMg11 cuboctahedra that share corners with six equivalent Mg(7)RbMg11 cuboctahedra, corners with eight equivalent Mg(5)RbMg10Cu cuboctahedra, edges with two equivalent Rb(1)Mg10Cu2 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, edges with four equivalent Mg(5)RbMg10Cu cuboctahedra,  a faceface with one Rb(1)Mg10Cu2 cuboctahedra,  a faceface with one Mg(2)Mg12 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, faces with two equivalent Mg(7)RbMg11 cuboctahedra, faces with three equivalent Mg(1)Mg12 cuboctahedra, faces with three equivalent Cu(1)Rb2Mg10 cuboctahedra, and faces with four equivalent Mg(5)RbMg10Cu cuboctahedra. Cu(1) is bonded to two equivalent Rb(1), two equivalent Mg(6), four equivalent Mg(3), and four equivalent Mg(5) atoms to form CuRb2Mg10 cuboctahedra that share corners with four equivalent Mg(2)Mg12 cuboctahedra, corners with six equivalent Cu(1)Rb2Mg10 cuboctahedra, corners with eight equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Rb(1)Mg10Cu2 cuboctahedra, edges with four equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, edges with eight equivalent Mg(5)RbMg10Cu cuboctahedra, faces with two equivalent Rb(1)Mg10Cu2 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with four equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, faces with four equivalent Mg(5)RbMg10Cu cuboctahedra, and faces with six equivalent Mg(7)RbMg11 cuboctahedra.
RbMg14Cu crystallizes in the orthorhombic Amm2 space group. Rb(1) is bonded to two equivalent Mg(7), four equivalent Mg(3), four equivalent Mg(5), and two equivalent Cu(1) atoms to form RbMg10Cu2 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with six equivalent Rb(1)Mg10Cu2 cuboctahedra, corners with eight equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Cu(1)Rb2Mg10 cuboctahedra, edges with four equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, edges with four equivalent Mg(7)RbMg11 cuboctahedra, edges with eight equivalent Mg(5)RbMg10Cu cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Mg(7)RbMg11 cuboctahedra, faces with two equivalent Cu(1)Rb2Mg10 cuboctahedra, faces with four equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, and faces with four equivalent Mg(5)RbMg10Cu cuboctahedra. Both Rb(1)-Mg(7) bond lengths are 3.45 Å. There are two shorter (3.26 Å) and two longer (3.27 Å) Rb(1)-Mg(3) bond lengths. All Rb(1)-Mg(5) bond lengths are 3.40 Å. Both Rb(1)-Cu(1) bond lengths are 3.19 Å. There are seven inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(2), two equivalent Mg(6), four equivalent Mg(4), and four equivalent Mg(5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Rb(1)Mg10Cu2 cuboctahedra, corners with six equivalent Mg(1)Mg12 cuboctahedra, corners with eight equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with eight equivalent Mg(5)RbMg10Cu cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Cu(1)Rb2Mg10 cuboctahedra, faces with four equivalent Mg(4)Mg12 cuboctahedra, faces with four equivalent Mg(5)RbMg10Cu cuboctahedra, and faces with six equivalent Mg(7)RbMg11 cuboctahedra. Both Mg(1)-Mg(2) bond lengths are 3.19 Å. Both Mg(1)-Mg(6) bond lengths are 3.35 Å. There are two shorter (3.24 Å) and two longer (3.28 Å) Mg(1)-Mg(4) bond lengths. All Mg(1)-Mg(5) bond lengths are 3.12 Å. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(7), four equivalent Mg(4), and four equivalent Mg(5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Cu(1)Rb2Mg10 cuboctahedra, corners with six equivalent Mg(2)Mg12 cuboctahedra, corners with eight equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(7)RbMg11 cuboctahedra, edges with eight equivalent Mg(5)RbMg10Cu cuboctahedra, faces with two equivalent Rb(1)Mg10Cu2 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Mg(7)RbMg11 cuboctahedra, faces with four equivalent Mg(4)Mg12 cuboctahedra, and faces with four equivalent Mg(5)RbMg10Cu cuboctahedra. Both Mg(2)-Mg(7) bond lengths are 3.15 Å. There are two shorter (3.24 Å) and two longer (3.28 Å) Mg(2)-Mg(4) bond lengths. All Mg(2)-Mg(5) bond lengths are 3.17 Å. In the third Mg site, Mg(3) is bonded to two equivalent Rb(1), two equivalent Mg(3), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), and two equivalent Cu(1) atoms to form distorted MgRb2Mg8Cu2 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with four equivalent Mg(2)Mg12 cuboctahedra, corners with four equivalent Mg(4)Mg12 cuboctahedra, corners with six equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, edges with two equivalent Rb(1)Mg10Cu2 cuboctahedra, edges with two equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, edges with two equivalent Cu(1)Rb2Mg10 cuboctahedra, edges with four equivalent Mg(5)RbMg10Cu cuboctahedra, edges with four equivalent Mg(7)RbMg11 cuboctahedra, faces with two equivalent Rb(1)Mg10Cu2 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, faces with two equivalent Mg(7)RbMg11 cuboctahedra, faces with two equivalent Cu(1)Rb2Mg10 cuboctahedra, and faces with eight equivalent Mg(5)RbMg10Cu cuboctahedra. There is one shorter (3.07 Å) and one longer (3.31 Å) Mg(3)-Mg(3) bond length. Both Mg(3)-Mg(5) bond lengths are 3.34 Å. Both Mg(3)-Mg(6) bond lengths are 3.18 Å. Both Mg(3)-Mg(7) bond lengths are 3.37 Å. There is one shorter (3.20 Å) and one longer (3.33 Å) Mg(3)-Cu(1) bond length. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), two equivalent Mg(5), two equivalent Mg(6), and two equivalent Mg(7) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Rb(1)Mg10Cu2 cuboctahedra, corners with four equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, corners with four equivalent Cu(1)Rb2Mg10 cuboctahedra, corners with six equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with two equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(5)RbMg10Cu cuboctahedra, edges with four equivalent Mg(7)RbMg11 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, faces with two equivalent Mg(7)RbMg11 cuboctahedra, and faces with eight equivalent Mg(5)RbMg10Cu cuboctahedra. There is one shorter (3.15 Å) and one longer (3.23 Å) Mg(4)-Mg(4) bond length. Both Mg(4)-Mg(5) bond lengths are 3.13 Å. Both Mg(4)-Mg(6) bond lengths are 3.38 Å. Both Mg(4)-Mg(7) bond lengths are 3.09 Å. In the fifth Mg site, Mg(5) is bonded to one Rb(1), one Mg(1), one Mg(2), one Mg(3), one Mg(4), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), and one Cu(1) atom to form distorted MgRbMg10Cu cuboctahedra that share corners with four equivalent Mg(7)RbMg11 cuboctahedra, corners with ten equivalent Mg(5)RbMg10Cu cuboctahedra, edges with two equivalent Rb(1)Mg10Cu2 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with two equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, edges with two equivalent Mg(5)RbMg10Cu cuboctahedra, edges with two equivalent Mg(7)RbMg11 cuboctahedra, edges with two equivalent Cu(1)Rb2Mg10 cuboctahedra,  a faceface with one Rb(1)Mg10Cu2 cuboctahedra,  a faceface with one Mg(1)Mg12 cuboctahedra,  a faceface with one Mg(2)Mg12 cuboctahedra,  a faceface with one Cu(1)Rb2Mg10 cuboctahedra, faces with two equivalent Mg(7)RbMg11 cuboctahedra, faces with four equivalent Mg(4)Mg12 cuboctahedra, faces with four equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, and faces with four equivalent Mg(5)RbMg10Cu cuboctahedra. There is one shorter (3.08 Å) and one longer (3.31 Å) Mg(5)-Mg(5) bond length. There is one shorter (3.23 Å) and one longer (3.33 Å) Mg(5)-Mg(6) bond length. There is one shorter (3.16 Å) and one longer (3.37 Å) Mg(5)-Mg(7) bond length. The Mg(5)-Cu(1) bond length is 3.34 Å. In the sixth Mg site, Mg(6) is bonded in a distorted single-bond geometry to one Mg(1), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(7), four equivalent Mg(5), and one Cu(1) atom. Both Mg(6)-Mg(7) bond lengths are 3.21 Å. The Mg(6)-Cu(1) bond length is 3.11 Å. In the seventh Mg site, Mg(7) is bonded to one Rb(1), one Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(6), and four equivalent Mg(5) atoms to form distorted MgRbMg11 cuboctahedra that share corners with six equivalent Mg(7)RbMg11 cuboctahedra, corners with eight equivalent Mg(5)RbMg10Cu cuboctahedra, edges with two equivalent Rb(1)Mg10Cu2 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, edges with four equivalent Mg(5)RbMg10Cu cuboctahedra,  a faceface with one Rb(1)Mg10Cu2 cuboctahedra,  a faceface with one Mg(2)Mg12 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, faces with two equivalent Mg(7)RbMg11 cuboctahedra, faces with three equivalent Mg(1)Mg12 cuboctahedra, faces with three equivalent Cu(1)Rb2Mg10 cuboctahedra, and faces with four equivalent Mg(5)RbMg10Cu cuboctahedra. Cu(1) is bonded to two equivalent Rb(1), two equivalent Mg(6), four equivalent Mg(3), and four equivalent Mg(5) atoms to form CuRb2Mg10 cuboctahedra that share corners with four equivalent Mg(2)Mg12 cuboctahedra, corners with six equivalent Cu(1)Rb2Mg10 cuboctahedra, corners with eight equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Rb(1)Mg10Cu2 cuboctahedra, edges with four equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, edges with eight equivalent Mg(5)RbMg10Cu cuboctahedra, faces with two equivalent Rb(1)Mg10Cu2 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with four equivalent Mg(3)Rb2Mg8Cu2 cuboctahedra, faces with four equivalent Mg(5)RbMg10Cu cuboctahedra, and faces with six equivalent Mg(7)RbMg11 cuboctahedra.