Mg2U4S2O27 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded in a 6-coordinate geometry to one O(2), one O(7), one O(8), one O(9), and two equivalent O(4) atoms. U(1) is bonded to one O(3), one O(4), one O(5), one O(6), and three equivalent O(1) atoms to form distorted UO7 pentagonal bipyramids that share corners with two equivalent U(1)O7 pentagonal bipyramids, corners with two equivalent S(1)O4 tetrahedra, and edges with two equivalent U(1)O7 pentagonal bipyramids. S(1) is bonded to two equivalent O(5) and two equivalent O(6) atoms to form SO4 tetrahedra that share corners with four equivalent U(1)O7 pentagonal bipyramids. There are nine inequivalent O sites. In the first O site, O(6) is bonded in a distorted bent 120 degrees geometry to one U(1) and one S(1) atom. In the second O site, O(7) is bonded in a single-bond geometry to one Mg(1) atom. In the third O site, O(8) is bonded in a single-bond geometry to one Mg(1) atom. In the fourth O site, O(9) is bonded in a linear geometry to two equivalent Mg(1) atoms. In the fifth O site, O(1) is bonded in a distorted trigonal planar geometry to three equivalent U(1) atoms. In the sixth O site, O(2) is bonded in a single-bond geometry to one Mg(1) atom. In the seventh O site, O(3) is bonded in a single-bond geometry to one U(1) atom. In the eighth O site, O(4) is bonded in a bent 150 degrees geometry to one Mg(1) and one U(1) atom. In the ninth O site, O(5) is bonded in a distorted single-bond geometry to one U(1) and one S(1) atom.
Mg2U4S2O27 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded in a 6-coordinate geometry to one O(2), one O(7), one O(8), one O(9), and two equivalent O(4) atoms. The Mg(1)-O(2) bond length is 2.05 Å. The Mg(1)-O(7) bond length is 2.32 Å. The Mg(1)-O(8) bond length is 2.18 Å. The Mg(1)-O(9) bond length is 1.98 Å. Both Mg(1)-O(4) bond lengths are 2.07 Å. U(1) is bonded to one O(3), one O(4), one O(5), one O(6), and three equivalent O(1) atoms to form distorted UO7 pentagonal bipyramids that share corners with two equivalent U(1)O7 pentagonal bipyramids, corners with two equivalent S(1)O4 tetrahedra, and edges with two equivalent U(1)O7 pentagonal bipyramids. The U(1)-O(3) bond length is 1.80 Å. The U(1)-O(4) bond length is 1.87 Å. The U(1)-O(5) bond length is 2.47 Å. The U(1)-O(6) bond length is 2.45 Å. There are a spread of U(1)-O(1) bond distances ranging from 2.22-2.33 Å. S(1) is bonded to two equivalent O(5) and two equivalent O(6) atoms to form SO4 tetrahedra that share corners with four equivalent U(1)O7 pentagonal bipyramids. Both S(1)-O(5) bond lengths are 1.49 Å. Both S(1)-O(6) bond lengths are 1.49 Å. There are nine inequivalent O sites. In the first O site, O(6) is bonded in a distorted bent 120 degrees geometry to one U(1) and one S(1) atom. In the second O site, O(7) is bonded in a single-bond geometry to one Mg(1) atom. In the third O site, O(8) is bonded in a single-bond geometry to one Mg(1) atom. In the fourth O site, O(9) is bonded in a linear geometry to two equivalent Mg(1) atoms. In the fifth O site, O(1) is bonded in a distorted trigonal planar geometry to three equivalent U(1) atoms. In the sixth O site, O(2) is bonded in a single-bond geometry to one Mg(1) atom. In the seventh O site, O(3) is bonded in a single-bond geometry to one U(1) atom. In the eighth O site, O(4) is bonded in a bent 150 degrees geometry to one Mg(1) and one U(1) atom. In the ninth O site, O(5) is bonded in a distorted single-bond geometry to one U(1) and one S(1) atom.