MgCu2(GeO3)2 crystallizes in the orthorhombic Pmm2 space group. Mg(1) is bonded in a 5-coordinate geometry to one O(2) and four equivalent O(4) atoms. Cu(1) is bonded in a 4-coordinate geometry to two equivalent O(3) and two equivalent O(4) atoms. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form corner-sharing GeO4 tetrahedra. In the second Ge site, Ge(2) is bonded to two equivalent O(2) and two equivalent O(4) atoms to form corner-sharing GeO4 tetrahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to two equivalent Ge(1) atoms. In the second O site, O(2) is bonded in a trigonal planar geometry to one Mg(1) and two equivalent Ge(2) atoms. In the third O site, O(3) is bonded in a trigonal non-coplanar geometry to two equivalent Cu(1) and one Ge(1) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to two equivalent Mg(1), two equivalent Cu(1), and one Ge(2) atom.
MgCu2(GeO3)2 crystallizes in the orthorhombic Pmm2 space group. Mg(1) is bonded in a 5-coordinate geometry to one O(2) and four equivalent O(4) atoms. The Mg(1)-O(2) bond length is 1.97 Å. All Mg(1)-O(4) bond lengths are 2.20 Å. Cu(1) is bonded in a 4-coordinate geometry to two equivalent O(3) and two equivalent O(4) atoms. Both Cu(1)-O(3) bond lengths are 1.95 Å. Both Cu(1)-O(4) bond lengths are 2.35 Å. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form corner-sharing GeO4 tetrahedra. Both Ge(1)-O(1) bond lengths are 1.86 Å. Both Ge(1)-O(3) bond lengths are 1.77 Å. In the second Ge site, Ge(2) is bonded to two equivalent O(2) and two equivalent O(4) atoms to form corner-sharing GeO4 tetrahedra. Both Ge(2)-O(2) bond lengths are 1.86 Å. Both Ge(2)-O(4) bond lengths are 1.84 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to two equivalent Ge(1) atoms. In the second O site, O(2) is bonded in a trigonal planar geometry to one Mg(1) and two equivalent Ge(2) atoms. In the third O site, O(3) is bonded in a trigonal non-coplanar geometry to two equivalent Cu(1) and one Ge(1) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to two equivalent Mg(1), two equivalent Cu(1), and one Ge(2) atom.