Mg19Ge5 crystallizes in the cubic P-43m space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 12-coordinate geometry to four equivalent Mg(3) and eight equivalent Mg(2) atoms. In the second Mg site, Mg(2) is bonded to one Mg(3), two equivalent Mg(1), five equivalent Mg(2), one Ge(2), and three equivalent Ge(1) atoms to form distorted MgMg8Ge4 cuboctahedra that share corners with four equivalent Mg(3)Mg9Ge3 cuboctahedra, corners with fourteen equivalent Mg(2)Mg8Ge4 cuboctahedra, edges with two equivalent Mg(3)Mg9Ge3 cuboctahedra, edges with four equivalent Mg(2)Mg8Ge4 cuboctahedra, faces with five equivalent Mg(3)Mg9Ge3 cuboctahedra, and faces with thirteen equivalent Mg(2)Mg8Ge4 cuboctahedra. In the third Mg site, Mg(3) is bonded to three equivalent Mg(1), three equivalent Mg(2), three equivalent Mg(3), and three equivalent Ge(1) atoms to form distorted MgMg9Ge3 cuboctahedra that share corners with six equivalent Mg(3)Mg9Ge3 cuboctahedra, corners with twelve equivalent Mg(2)Mg8Ge4 cuboctahedra, edges with six equivalent Mg(2)Mg8Ge4 cuboctahedra, faces with three equivalent Mg(3)Mg9Ge3 cuboctahedra, and faces with fifteen equivalent Mg(2)Mg8Ge4 cuboctahedra. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 12-coordinate geometry to three equivalent Mg(3) and nine equivalent Mg(2) atoms. In the second Ge site, Ge(2) is bonded in a 12-coordinate geometry to twelve equivalent Mg(2) atoms.
Mg19Ge5 crystallizes in the cubic P-43m space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 12-coordinate geometry to four equivalent Mg(3) and eight equivalent Mg(2) atoms. All Mg(1)-Mg(3) bond lengths are 3.38 Å. All Mg(1)-Mg(2) bond lengths are 3.39 Å. In the second Mg site, Mg(2) is bonded to one Mg(3), two equivalent Mg(1), five equivalent Mg(2), one Ge(2), and three equivalent Ge(1) atoms to form distorted MgMg8Ge4 cuboctahedra that share corners with four equivalent Mg(3)Mg9Ge3 cuboctahedra, corners with fourteen equivalent Mg(2)Mg8Ge4 cuboctahedra, edges with two equivalent Mg(3)Mg9Ge3 cuboctahedra, edges with four equivalent Mg(2)Mg8Ge4 cuboctahedra, faces with five equivalent Mg(3)Mg9Ge3 cuboctahedra, and faces with thirteen equivalent Mg(2)Mg8Ge4 cuboctahedra. The Mg(2)-Mg(3) bond length is 2.89 Å. There are three shorter (2.87 Å) and two longer (2.89 Å) Mg(2)-Mg(2) bond lengths. The Mg(2)-Ge(2) bond length is 3.37 Å. There are two shorter (3.38 Å) and one longer (3.39 Å) Mg(2)-Ge(1) bond length. In the third Mg site, Mg(3) is bonded to three equivalent Mg(1), three equivalent Mg(2), three equivalent Mg(3), and three equivalent Ge(1) atoms to form distorted MgMg9Ge3 cuboctahedra that share corners with six equivalent Mg(3)Mg9Ge3 cuboctahedra, corners with twelve equivalent Mg(2)Mg8Ge4 cuboctahedra, edges with six equivalent Mg(2)Mg8Ge4 cuboctahedra, faces with three equivalent Mg(3)Mg9Ge3 cuboctahedra, and faces with fifteen equivalent Mg(2)Mg8Ge4 cuboctahedra. All Mg(3)-Mg(3) bond lengths are 2.89 Å. All Mg(3)-Ge(1) bond lengths are 3.38 Å. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 12-coordinate geometry to three equivalent Mg(3) and nine equivalent Mg(2) atoms. In the second Ge site, Ge(2) is bonded in a 12-coordinate geometry to twelve equivalent Mg(2) atoms.