Mg5Sc crystallizes in the orthorhombic Amm2 space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(5), and four equivalent Mg(4) atoms to form MgMg12 cuboctahedra that share corners with six equivalent Mg(3)Mg10Sc2 cuboctahedra, corners with six equivalent Mg(1)Mg12 cuboctahedra, corners with six equivalent Mg(2)Mg8Sc4 cuboctahedra, edges with three equivalent Mg(3)Mg10Sc2 cuboctahedra, edges with three equivalent Mg(2)Mg8Sc4 cuboctahedra, edges with four equivalent Mg(4)Mg10Sc2 cuboctahedra, edges with eight equivalent Sc(1)Mg10Sc2 cuboctahedra, faces with two equivalent Mg(3)Mg10Sc2 cuboctahedra, faces with two equivalent Mg(2)Mg8Sc4 cuboctahedra, faces with two equivalent Sc(1)Mg10Sc2 cuboctahedra, faces with four equivalent Mg(4)Mg10Sc2 cuboctahedra, faces with four equivalent Mg(1)Mg12 cuboctahedra, and faces with six equivalent Mg(5)Mg10Sc2 cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), and four equivalent Sc(1) atoms to form MgMg8Sc4 cuboctahedra that share corners with six equivalent Mg(3)Mg10Sc2 cuboctahedra, corners with six equivalent Mg(1)Mg12 cuboctahedra, corners with six equivalent Mg(2)Mg8Sc4 cuboctahedra, edges with three equivalent Mg(3)Mg10Sc2 cuboctahedra, edges with three equivalent Mg(1)Mg12 cuboctahedra, edges with four equivalent Sc(1)Mg10Sc2 cuboctahedra, edges with eight equivalent Mg(5)Mg10Sc2 cuboctahedra, faces with two equivalent Mg(3)Mg10Sc2 cuboctahedra, faces with two equivalent Mg(5)Mg10Sc2 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with four equivalent Mg(2)Mg8Sc4 cuboctahedra, faces with four equivalent Sc(1)Mg10Sc2 cuboctahedra, and faces with six equivalent Mg(4)Mg10Sc2 cuboctahedra. In the third Mg site, Mg(3) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), four equivalent Mg(5), and two equivalent Sc(1) atoms to form MgMg10Sc2 cuboctahedra that share corners with six equivalent Mg(3)Mg10Sc2 cuboctahedra, corners with six equivalent Mg(1)Mg12 cuboctahedra, corners with six equivalent Mg(2)Mg8Sc4 cuboctahedra, edges with three equivalent Mg(1)Mg12 cuboctahedra, edges with three equivalent Mg(2)Mg8Sc4 cuboctahedra, edges with four equivalent Mg(5)Mg10Sc2 cuboctahedra, edges with eight equivalent Mg(4)Mg10Sc2 cuboctahedra, faces with two equivalent Mg(4)Mg10Sc2 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Mg(2)Mg8Sc4 cuboctahedra, faces with four equivalent Mg(3)Mg10Sc2 cuboctahedra, faces with four equivalent Mg(5)Mg10Sc2 cuboctahedra, and faces with six equivalent Sc(1)Mg10Sc2 cuboctahedra. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(2), two equivalent Mg(4), two equivalent Mg(5), four equivalent Mg(1), and two equivalent Sc(1) atoms to form MgMg10Sc2 cuboctahedra that share corners with six equivalent Mg(4)Mg10Sc2 cuboctahedra, corners with six equivalent Mg(5)Mg10Sc2 cuboctahedra, corners with six equivalent Sc(1)Mg10Sc2 cuboctahedra, edges with three equivalent Mg(5)Mg10Sc2 cuboctahedra, edges with three equivalent Sc(1)Mg10Sc2 cuboctahedra, edges with four equivalent Mg(1)Mg12 cuboctahedra, edges with eight equivalent Mg(3)Mg10Sc2 cuboctahedra, faces with two equivalent Mg(3)Mg10Sc2 cuboctahedra, faces with two equivalent Mg(5)Mg10Sc2 cuboctahedra, faces with two equivalent Sc(1)Mg10Sc2 cuboctahedra, faces with four equivalent Mg(4)Mg10Sc2 cuboctahedra, faces with four equivalent Mg(1)Mg12 cuboctahedra, and faces with six equivalent Mg(2)Mg8Sc4 cuboctahedra. In the fifth Mg site, Mg(5) is bonded to two equivalent Mg(1), two equivalent Mg(4), two equivalent Mg(5), four equivalent Mg(3), and two equivalent Sc(1) atoms to form MgMg10Sc2 cuboctahedra that share corners with six equivalent Mg(4)Mg10Sc2 cuboctahedra, corners with six equivalent Mg(5)Mg10Sc2 cuboctahedra, corners with six equivalent Sc(1)Mg10Sc2 cuboctahedra, edges with three equivalent Mg(4)Mg10Sc2 cuboctahedra, edges with three equivalent Sc(1)Mg10Sc2 cuboctahedra, edges with four equivalent Mg(3)Mg10Sc2 cuboctahedra, edges with eight equivalent Mg(2)Mg8Sc4 cuboctahedra, faces with two equivalent Mg(4)Mg10Sc2 cuboctahedra, faces with two equivalent Mg(2)Mg8Sc4 cuboctahedra, faces with two equivalent Sc(1)Mg10Sc2 cuboctahedra, faces with four equivalent Mg(3)Mg10Sc2 cuboctahedra, faces with four equivalent Mg(5)Mg10Sc2 cuboctahedra, and faces with six equivalent Mg(1)Mg12 cuboctahedra. Sc(1) is bonded to two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(5), four equivalent Mg(2), and two equivalent Sc(1) atoms to form ScMg10Sc2 cuboctahedra that share corners with six equivalent Mg(4)Mg10Sc2 cuboctahedra, corners with six equivalent Mg(5)Mg10Sc2 cuboctahedra, corners with six equivalent Sc(1)Mg10Sc2 cuboctahedra, edges with three equivalent Mg(4)Mg10Sc2 cuboctahedra, edges with three equivalent Mg(5)Mg10Sc2 cuboctahedra, edges with four equivalent Mg(2)Mg8Sc4 cuboctahedra, edges with eight equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Mg(4)Mg10Sc2 cuboctahedra, faces with two equivalent Mg(5)Mg10Sc2 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with four equivalent Mg(2)Mg8Sc4 cuboctahedra, faces with four equivalent Sc(1)Mg10Sc2 cuboctahedra, and faces with six equivalent Mg(3)Mg10Sc2 cuboctahedra.
Mg5Sc crystallizes in the orthorhombic Amm2 space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(5), and four equivalent Mg(4) atoms to form MgMg12 cuboctahedra that share corners with six equivalent Mg(3)Mg10Sc2 cuboctahedra, corners with six equivalent Mg(1)Mg12 cuboctahedra, corners with six equivalent Mg(2)Mg8Sc4 cuboctahedra, edges with three equivalent Mg(3)Mg10Sc2 cuboctahedra, edges with three equivalent Mg(2)Mg8Sc4 cuboctahedra, edges with four equivalent Mg(4)Mg10Sc2 cuboctahedra, edges with eight equivalent Sc(1)Mg10Sc2 cuboctahedra, faces with two equivalent Mg(3)Mg10Sc2 cuboctahedra, faces with two equivalent Mg(2)Mg8Sc4 cuboctahedra, faces with two equivalent Sc(1)Mg10Sc2 cuboctahedra, faces with four equivalent Mg(4)Mg10Sc2 cuboctahedra, faces with four equivalent Mg(1)Mg12 cuboctahedra, and faces with six equivalent Mg(5)Mg10Sc2 cuboctahedra. Both Mg(1)-Mg(1) bond lengths are 3.28 Å. Both Mg(1)-Mg(2) bond lengths are 3.15 Å. Both Mg(1)-Mg(3) bond lengths are 3.22 Å. Both Mg(1)-Mg(5) bond lengths are 3.23 Å. All Mg(1)-Mg(4) bond lengths are 3.15 Å. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), and four equivalent Sc(1) atoms to form MgMg8Sc4 cuboctahedra that share corners with six equivalent Mg(3)Mg10Sc2 cuboctahedra, corners with six equivalent Mg(1)Mg12 cuboctahedra, corners with six equivalent Mg(2)Mg8Sc4 cuboctahedra, edges with three equivalent Mg(3)Mg10Sc2 cuboctahedra, edges with three equivalent Mg(1)Mg12 cuboctahedra, edges with four equivalent Sc(1)Mg10Sc2 cuboctahedra, edges with eight equivalent Mg(5)Mg10Sc2 cuboctahedra, faces with two equivalent Mg(3)Mg10Sc2 cuboctahedra, faces with two equivalent Mg(5)Mg10Sc2 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with four equivalent Mg(2)Mg8Sc4 cuboctahedra, faces with four equivalent Sc(1)Mg10Sc2 cuboctahedra, and faces with six equivalent Mg(4)Mg10Sc2 cuboctahedra. Both Mg(2)-Mg(2) bond lengths are 3.28 Å. Both Mg(2)-Mg(3) bond lengths are 3.13 Å. Both Mg(2)-Mg(4) bond lengths are 3.22 Å. All Mg(2)-Sc(1) bond lengths are 3.14 Å. In the third Mg site, Mg(3) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), four equivalent Mg(5), and two equivalent Sc(1) atoms to form MgMg10Sc2 cuboctahedra that share corners with six equivalent Mg(3)Mg10Sc2 cuboctahedra, corners with six equivalent Mg(1)Mg12 cuboctahedra, corners with six equivalent Mg(2)Mg8Sc4 cuboctahedra, edges with three equivalent Mg(1)Mg12 cuboctahedra, edges with three equivalent Mg(2)Mg8Sc4 cuboctahedra, edges with four equivalent Mg(5)Mg10Sc2 cuboctahedra, edges with eight equivalent Mg(4)Mg10Sc2 cuboctahedra, faces with two equivalent Mg(4)Mg10Sc2 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Mg(2)Mg8Sc4 cuboctahedra, faces with four equivalent Mg(3)Mg10Sc2 cuboctahedra, faces with four equivalent Mg(5)Mg10Sc2 cuboctahedra, and faces with six equivalent Sc(1)Mg10Sc2 cuboctahedra. Both Mg(3)-Mg(3) bond lengths are 3.28 Å. All Mg(3)-Mg(5) bond lengths are 3.17 Å. Both Mg(3)-Sc(1) bond lengths are 3.22 Å. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(2), two equivalent Mg(4), two equivalent Mg(5), four equivalent Mg(1), and two equivalent Sc(1) atoms to form MgMg10Sc2 cuboctahedra that share corners with six equivalent Mg(4)Mg10Sc2 cuboctahedra, corners with six equivalent Mg(5)Mg10Sc2 cuboctahedra, corners with six equivalent Sc(1)Mg10Sc2 cuboctahedra, edges with three equivalent Mg(5)Mg10Sc2 cuboctahedra, edges with three equivalent Sc(1)Mg10Sc2 cuboctahedra, edges with four equivalent Mg(1)Mg12 cuboctahedra, edges with eight equivalent Mg(3)Mg10Sc2 cuboctahedra, faces with two equivalent Mg(3)Mg10Sc2 cuboctahedra, faces with two equivalent Mg(5)Mg10Sc2 cuboctahedra, faces with two equivalent Sc(1)Mg10Sc2 cuboctahedra, faces with four equivalent Mg(4)Mg10Sc2 cuboctahedra, faces with four equivalent Mg(1)Mg12 cuboctahedra, and faces with six equivalent Mg(2)Mg8Sc4 cuboctahedra. Both Mg(4)-Mg(4) bond lengths are 3.28 Å. Both Mg(4)-Mg(5) bond lengths are 3.16 Å. Both Mg(4)-Sc(1) bond lengths are 3.12 Å. In the fifth Mg site, Mg(5) is bonded to two equivalent Mg(1), two equivalent Mg(4), two equivalent Mg(5), four equivalent Mg(3), and two equivalent Sc(1) atoms to form MgMg10Sc2 cuboctahedra that share corners with six equivalent Mg(4)Mg10Sc2 cuboctahedra, corners with six equivalent Mg(5)Mg10Sc2 cuboctahedra, corners with six equivalent Sc(1)Mg10Sc2 cuboctahedra, edges with three equivalent Mg(4)Mg10Sc2 cuboctahedra, edges with three equivalent Sc(1)Mg10Sc2 cuboctahedra, edges with four equivalent Mg(3)Mg10Sc2 cuboctahedra, edges with eight equivalent Mg(2)Mg8Sc4 cuboctahedra, faces with two equivalent Mg(4)Mg10Sc2 cuboctahedra, faces with two equivalent Mg(2)Mg8Sc4 cuboctahedra, faces with two equivalent Sc(1)Mg10Sc2 cuboctahedra, faces with four equivalent Mg(3)Mg10Sc2 cuboctahedra, faces with four equivalent Mg(5)Mg10Sc2 cuboctahedra, and faces with six equivalent Mg(1)Mg12 cuboctahedra. Both Mg(5)-Mg(5) bond lengths are 3.28 Å. Both Mg(5)-Sc(1) bond lengths are 3.22 Å. Sc(1) is bonded to two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(5), four equivalent Mg(2), and two equivalent Sc(1) atoms to form ScMg10Sc2 cuboctahedra that share corners with six equivalent Mg(4)Mg10Sc2 cuboctahedra, corners with six equivalent Mg(5)Mg10Sc2 cuboctahedra, corners with six equivalent Sc(1)Mg10Sc2 cuboctahedra, edges with three equivalent Mg(4)Mg10Sc2 cuboctahedra, edges with three equivalent Mg(5)Mg10Sc2 cuboctahedra, edges with four equivalent Mg(2)Mg8Sc4 cuboctahedra, edges with eight equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Mg(4)Mg10Sc2 cuboctahedra, faces with two equivalent Mg(5)Mg10Sc2 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with four equivalent Mg(2)Mg8Sc4 cuboctahedra, faces with four equivalent Sc(1)Mg10Sc2 cuboctahedra, and faces with six equivalent Mg(3)Mg10Sc2 cuboctahedra. Both Sc(1)-Sc(1) bond lengths are 3.28 Å.