MgU(MoO4)4 crystallizes in the monoclinic P2/c space group. Mg(1) is bonded to one O(4), two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms to form MgO7 pentagonal bipyramids that share corners with two equivalent Mo(1)O6 octahedra, corners with two equivalent Mo(2)O6 octahedra, corners with two equivalent U(1)O7 pentagonal bipyramids, and edges with two equivalent Mo(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 25-28°. U(1) is bonded to one O(9), two equivalent O(1), two equivalent O(5), and two equivalent O(8) atoms to form UO7 pentagonal bipyramids that share corners with two equivalent Mo(1)O6 octahedra, corners with two equivalent Mo(2)O6 octahedra, corners with two equivalent Mg(1)O7 pentagonal bipyramids, and edges with two equivalent Mo(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 25-30°. There are two inequivalent Mo sites. In the first Mo site, Mo(1) is bonded to one O(1), one O(2), one O(3), one O(7), one O(8), and one O(9) atom to form distorted MoO6 octahedra that share  a cornercorner with one Mo(1)O6 octahedra, corners with two equivalent Mo(2)O6 octahedra,  a cornercorner with one Mg(1)O7 pentagonal bipyramid,  a cornercorner with one U(1)O7 pentagonal bipyramid,  an edgeedge with one Mo(2)O6 octahedra, and  an edgeedge with one U(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 7-43°. In the second Mo site, Mo(2) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form distorted MoO6 octahedra that share  a cornercorner with one Mo(2)O6 octahedra, corners with two equivalent Mo(1)O6 octahedra,  a cornercorner with one Mg(1)O7 pentagonal bipyramid,  a cornercorner with one U(1)O7 pentagonal bipyramid,  an edgeedge with one Mo(1)O6 octahedra, and  an edgeedge with one Mg(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 7-48°. There are nine inequivalent O sites. In the first O site, O(9) is bonded in a trigonal planar geometry to one U(1) and two equivalent Mo(1) atoms. In the second O site, O(1) is bonded in a 3-coordinate geometry to one U(1), one Mo(1), and one Mo(2) atom. In the third O site, O(2) is bonded in a linear geometry to one Mo(1) and one Mo(2) atom. In the fourth O site, O(3) is bonded in a linear geometry to one Mo(1) and one Mo(2) atom. In the fifth O site, O(4) is bonded in a trigonal planar geometry to one Mg(1) and two equivalent Mo(2) atoms. In the sixth O site, O(5) is bonded in a linear geometry to one Mg(1) and one U(1) atom. In the seventh O site, O(6) is bonded in a bent 150 degrees geometry to one Mg(1) and one Mo(2) atom. In the eighth O site, O(7) is bonded in a 3-coordinate geometry to one Mg(1), one Mo(1), and one Mo(2) atom. In the ninth O site, O(8) is bonded in a bent 150 degrees geometry to one U(1) and one Mo(1) atom.
MgU(MoO4)4 crystallizes in the monoclinic P2/c space group. Mg(1) is bonded to one O(4), two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms to form MgO7 pentagonal bipyramids that share corners with two equivalent Mo(1)O6 octahedra, corners with two equivalent Mo(2)O6 octahedra, corners with two equivalent U(1)O7 pentagonal bipyramids, and edges with two equivalent Mo(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 25-28°. The Mg(1)-O(4) bond length is 2.35 Å. Both Mg(1)-O(5) bond lengths are 2.14 Å. Both Mg(1)-O(6) bond lengths are 2.25 Å. Both Mg(1)-O(7) bond lengths are 2.31 Å. U(1) is bonded to one O(9), two equivalent O(1), two equivalent O(5), and two equivalent O(8) atoms to form UO7 pentagonal bipyramids that share corners with two equivalent Mo(1)O6 octahedra, corners with two equivalent Mo(2)O6 octahedra, corners with two equivalent Mg(1)O7 pentagonal bipyramids, and edges with two equivalent Mo(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 25-30°. The U(1)-O(9) bond length is 2.34 Å. Both U(1)-O(1) bond lengths are 2.33 Å. Both U(1)-O(5) bond lengths are 1.86 Å. Both U(1)-O(8) bond lengths are 2.31 Å. There are two inequivalent Mo sites. In the first Mo site, Mo(1) is bonded to one O(1), one O(2), one O(3), one O(7), one O(8), and one O(9) atom to form distorted MoO6 octahedra that share  a cornercorner with one Mo(1)O6 octahedra, corners with two equivalent Mo(2)O6 octahedra,  a cornercorner with one Mg(1)O7 pentagonal bipyramid,  a cornercorner with one U(1)O7 pentagonal bipyramid,  an edgeedge with one Mo(2)O6 octahedra, and  an edgeedge with one U(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 7-43°. The Mo(1)-O(1) bond length is 2.18 Å. The Mo(1)-O(2) bond length is 2.22 Å. The Mo(1)-O(3) bond length is 1.77 Å. The Mo(1)-O(7) bond length is 1.84 Å. The Mo(1)-O(8) bond length is 1.79 Å. The Mo(1)-O(9) bond length is 2.03 Å. In the second Mo site, Mo(2) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form distorted MoO6 octahedra that share  a cornercorner with one Mo(2)O6 octahedra, corners with two equivalent Mo(1)O6 octahedra,  a cornercorner with one Mg(1)O7 pentagonal bipyramid,  a cornercorner with one U(1)O7 pentagonal bipyramid,  an edgeedge with one Mo(1)O6 octahedra, and  an edgeedge with one Mg(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 7-48°. The Mo(2)-O(1) bond length is 1.94 Å. The Mo(2)-O(2) bond length is 1.79 Å. The Mo(2)-O(3) bond length is 2.23 Å. The Mo(2)-O(4) bond length is 1.95 Å. The Mo(2)-O(6) bond length is 1.75 Å. The Mo(2)-O(7) bond length is 2.27 Å. There are nine inequivalent O sites. In the first O site, O(9) is bonded in a trigonal planar geometry to one U(1) and two equivalent Mo(1) atoms. In the second O site, O(1) is bonded in a 3-coordinate geometry to one U(1), one Mo(1), and one Mo(2) atom. In the third O site, O(2) is bonded in a linear geometry to one Mo(1) and one Mo(2) atom. In the fourth O site, O(3) is bonded in a linear geometry to one Mo(1) and one Mo(2) atom. In the fifth O site, O(4) is bonded in a trigonal planar geometry to one Mg(1) and two equivalent Mo(2) atoms. In the sixth O site, O(5) is bonded in a linear geometry to one Mg(1) and one U(1) atom. In the seventh O site, O(6) is bonded in a bent 150 degrees geometry to one Mg(1) and one Mo(2) atom. In the eighth O site, O(7) is bonded in a 3-coordinate geometry to one Mg(1), one Mo(1), and one Mo(2) atom. In the ninth O site, O(8) is bonded in a bent 150 degrees geometry to one U(1) and one Mo(1) atom.