Mg3Mo crystallizes in the orthorhombic Pmm2 space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), four equivalent Mg(3), and four equivalent Mo(1) atoms to form distorted MgMg8Mo4 cuboctahedra that share corners with eight equivalent Mo(1)Mg10Mo2 cuboctahedra, corners with ten equivalent Mg(1)Mg8Mo4 cuboctahedra, edges with two equivalent Mg(1)Mg8Mo4 cuboctahedra, edges with four equivalent Mo(1)Mg10Mo2 cuboctahedra, faces with four equivalent Mg(1)Mg8Mo4 cuboctahedra, and faces with four equivalent Mo(1)Mg10Mo2 cuboctahedra. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to two equivalent Mg(1) and four equivalent Mo(1) atoms. In the third Mg site, Mg(3) is bonded in a distorted bent 120 degrees geometry to four equivalent Mg(1) and two equivalent Mo(1) atoms. Mo(1) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Mo(1) atoms to form distorted MoMg10Mo2 cuboctahedra that share corners with eight equivalent Mg(1)Mg8Mo4 cuboctahedra, corners with ten equivalent Mo(1)Mg10Mo2 cuboctahedra, edges with two equivalent Mo(1)Mg10Mo2 cuboctahedra, edges with four equivalent Mg(1)Mg8Mo4 cuboctahedra, faces with four equivalent Mg(1)Mg8Mo4 cuboctahedra, and faces with four equivalent Mo(1)Mg10Mo2 cuboctahedra.
Mg3Mo crystallizes in the orthorhombic Pmm2 space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), four equivalent Mg(3), and four equivalent Mo(1) atoms to form distorted MgMg8Mo4 cuboctahedra that share corners with eight equivalent Mo(1)Mg10Mo2 cuboctahedra, corners with ten equivalent Mg(1)Mg8Mo4 cuboctahedra, edges with two equivalent Mg(1)Mg8Mo4 cuboctahedra, edges with four equivalent Mo(1)Mg10Mo2 cuboctahedra, faces with four equivalent Mg(1)Mg8Mo4 cuboctahedra, and faces with four equivalent Mo(1)Mg10Mo2 cuboctahedra. Both Mg(1)-Mg(1) bond lengths are 2.87 Å. Both Mg(1)-Mg(2) bond lengths are 3.04 Å. All Mg(1)-Mg(3) bond lengths are 3.06 Å. There are two shorter (3.06 Å) and two longer (3.07 Å) Mg(1)-Mo(1) bond lengths. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to two equivalent Mg(1) and four equivalent Mo(1) atoms. All Mg(2)-Mo(1) bond lengths are 2.99 Å. In the third Mg site, Mg(3) is bonded in a distorted bent 120 degrees geometry to four equivalent Mg(1) and two equivalent Mo(1) atoms. Both Mg(3)-Mo(1) bond lengths are 2.91 Å. Mo(1) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Mo(1) atoms to form distorted MoMg10Mo2 cuboctahedra that share corners with eight equivalent Mg(1)Mg8Mo4 cuboctahedra, corners with ten equivalent Mo(1)Mg10Mo2 cuboctahedra, edges with two equivalent Mo(1)Mg10Mo2 cuboctahedra, edges with four equivalent Mg(1)Mg8Mo4 cuboctahedra, faces with four equivalent Mg(1)Mg8Mo4 cuboctahedra, and faces with four equivalent Mo(1)Mg10Mo2 cuboctahedra. Both Mo(1)-Mo(1) bond lengths are 2.87 Å.