MgGe4(MoO6)2 crystallizes in the monoclinic C2 space group. Mg(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form distorted MgO6 pentagonal pyramids that share corners with four equivalent Ge(1)O4 tetrahedra,  an edgeedge with one Mo(1)O6 octahedra, edges with two equivalent Mo(2)O6 octahedra, and edges with two equivalent Ge(2)O4 tetrahedra. There are two inequivalent Mo sites. In the first Mo site, Mo(1) is bonded to two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms to form MoO6 octahedra that share corners with two equivalent Ge(2)O4 tetrahedra, corners with four equivalent Ge(1)O4 tetrahedra, edges with two equivalent Mo(2)O6 octahedra, and  an edgeedge with one Mg(1)O6 pentagonal pyramid. In the second Mo site, Mo(2) is bonded to two equivalent O(3), two equivalent O(5), and two equivalent O(6) atoms to form MoO6 octahedra that share corners with two equivalent Ge(1)O4 tetrahedra, corners with four equivalent Ge(2)O4 tetrahedra, edges with two equivalent Mo(1)O6 octahedra, and edges with two equivalent Mg(1)O6 pentagonal pyramids. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded to one O(1), one O(2), one O(4), and one O(5) atom to form GeO4 tetrahedra that share  a cornercorner with one Mo(2)O6 octahedra, corners with two equivalent Mo(1)O6 octahedra, corners with two equivalent Mg(1)O6 pentagonal pyramids, and corners with two equivalent Ge(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 37-62°. In the second Ge site, Ge(2) is bonded to one O(1), one O(2), one O(3), and one O(6) atom to form GeO4 tetrahedra that share  a cornercorner with one Mo(1)O6 octahedra, corners with two equivalent Mo(2)O6 octahedra, corners with two equivalent Ge(1)O4 tetrahedra, and  an edgeedge with one Mg(1)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 39-60°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Ge(1) and one Ge(2) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mg(1), one Ge(1), and one Ge(2) atom. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1), one Mo(2), and one Ge(2) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Mo(1) and one Ge(1) atom. In the fifth O site, O(5) is bonded to one Mg(1), one Mo(1), one Mo(2), and one Ge(1) atom to form a mixture of distorted corner and edge-sharing OMgGeMo2 tetrahedra. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Mo(1), one Mo(2), and one Ge(2) atom.
MgGe4(MoO6)2 crystallizes in the monoclinic C2 space group. Mg(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form distorted MgO6 pentagonal pyramids that share corners with four equivalent Ge(1)O4 tetrahedra,  an edgeedge with one Mo(1)O6 octahedra, edges with two equivalent Mo(2)O6 octahedra, and edges with two equivalent Ge(2)O4 tetrahedra. Both Mg(1)-O(2) bond lengths are 2.27 Å. Both Mg(1)-O(3) bond lengths are 2.10 Å. Both Mg(1)-O(5) bond lengths are 2.24 Å. There are two inequivalent Mo sites. In the first Mo site, Mo(1) is bonded to two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms to form MoO6 octahedra that share corners with two equivalent Ge(2)O4 tetrahedra, corners with four equivalent Ge(1)O4 tetrahedra, edges with two equivalent Mo(2)O6 octahedra, and  an edgeedge with one Mg(1)O6 pentagonal pyramid. Both Mo(1)-O(4) bond lengths are 2.09 Å. Both Mo(1)-O(5) bond lengths are 2.26 Å. Both Mo(1)-O(6) bond lengths are 2.17 Å. In the second Mo site, Mo(2) is bonded to two equivalent O(3), two equivalent O(5), and two equivalent O(6) atoms to form MoO6 octahedra that share corners with two equivalent Ge(1)O4 tetrahedra, corners with four equivalent Ge(2)O4 tetrahedra, edges with two equivalent Mo(1)O6 octahedra, and edges with two equivalent Mg(1)O6 pentagonal pyramids. Both Mo(2)-O(3) bond lengths are 2.12 Å. Both Mo(2)-O(5) bond lengths are 2.19 Å. Both Mo(2)-O(6) bond lengths are 2.17 Å. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded to one O(1), one O(2), one O(4), and one O(5) atom to form GeO4 tetrahedra that share  a cornercorner with one Mo(2)O6 octahedra, corners with two equivalent Mo(1)O6 octahedra, corners with two equivalent Mg(1)O6 pentagonal pyramids, and corners with two equivalent Ge(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 37-62°. The Ge(1)-O(1) bond length is 1.77 Å. The Ge(1)-O(2) bond length is 1.80 Å. The Ge(1)-O(4) bond length is 1.71 Å. The Ge(1)-O(5) bond length is 1.81 Å. In the second Ge site, Ge(2) is bonded to one O(1), one O(2), one O(3), and one O(6) atom to form GeO4 tetrahedra that share  a cornercorner with one Mo(1)O6 octahedra, corners with two equivalent Mo(2)O6 octahedra, corners with two equivalent Ge(1)O4 tetrahedra, and  an edgeedge with one Mg(1)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 39-60°. The Ge(2)-O(1) bond length is 1.77 Å. The Ge(2)-O(2) bond length is 1.82 Å. The Ge(2)-O(3) bond length is 1.76 Å. The Ge(2)-O(6) bond length is 1.76 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Ge(1) and one Ge(2) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mg(1), one Ge(1), and one Ge(2) atom. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1), one Mo(2), and one Ge(2) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Mo(1) and one Ge(1) atom. In the fifth O site, O(5) is bonded to one Mg(1), one Mo(1), one Mo(2), and one Ge(1) atom to form a mixture of distorted corner and edge-sharing OMgGeMo2 tetrahedra. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Mo(1), one Mo(2), and one Ge(2) atom.