K2Mg(SO6)2 crystallizes in the monoclinic C2/m space group. K(1) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), one O(7), one O(8), and one O(9) atom. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1), two equivalent O(5), and two equivalent O(6) atoms to form MgO6 octahedra that share corners with two equivalent S(1)O4 tetrahedra. In the second Mg site, Mg(2) is bonded to two equivalent O(9) and four equivalent O(2) atoms to form distorted MgO6 octahedra that share corners with two equivalent S(2)O4 tetrahedra. There are two inequivalent S sites. In the first S site, S(1) is bonded to one O(5), one O(7), and two equivalent O(8) atoms to form SO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles are 18°. In the second S site, S(2) is bonded to one O(4), one O(9), and two equivalent O(3) atoms to form SO4 tetrahedra that share  a cornercorner with one Mg(2)O6 octahedra. The corner-sharing octahedral tilt angles are 38°. There are nine inequivalent O sites. In the first O site, O(5) is bonded in a distorted bent 150 degrees geometry to two equivalent K(1), one Mg(1), and one S(1) atom. In the second O site, O(6) is bonded in a distorted single-bond geometry to two equivalent K(1) and one Mg(1) atom. In the third O site, O(7) is bonded in a distorted trigonal planar geometry to two equivalent K(1) and one S(1) atom. In the fourth O site, O(8) is bonded in a distorted single-bond geometry to one K(1) and one S(1) atom. In the fifth O site, O(9) is bonded in a distorted bent 150 degrees geometry to two equivalent K(1), one Mg(2), and one S(2) atom. In the sixth O site, O(1) is bonded in a single-bond geometry to two equivalent K(1) and one Mg(1) atom. In the seventh O site, O(2) is bonded in a bent 120 degrees geometry to one K(1) and one Mg(2) atom. In the eighth O site, O(3) is bonded in a distorted single-bond geometry to one K(1) and one S(2) atom. In the ninth O site, O(4) is bonded in a distorted single-bond geometry to two equivalent K(1) and one S(2) atom.
K2Mg(SO6)2 crystallizes in the monoclinic C2/m space group. K(1) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), one O(7), one O(8), and one O(9) atom. The K(1)-O(1) bond length is 3.20 Å. The K(1)-O(2) bond length is 2.78 Å. The K(1)-O(3) bond length is 2.87 Å. The K(1)-O(4) bond length is 2.87 Å. The K(1)-O(5) bond length is 3.13 Å. The K(1)-O(6) bond length is 2.86 Å. The K(1)-O(7) bond length is 2.88 Å. The K(1)-O(8) bond length is 2.94 Å. The K(1)-O(9) bond length is 3.18 Å. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1), two equivalent O(5), and two equivalent O(6) atoms to form MgO6 octahedra that share corners with two equivalent S(1)O4 tetrahedra. Both Mg(1)-O(1) bond lengths are 2.04 Å. Both Mg(1)-O(5) bond lengths are 2.01 Å. Both Mg(1)-O(6) bond lengths are 2.02 Å. In the second Mg site, Mg(2) is bonded to two equivalent O(9) and four equivalent O(2) atoms to form distorted MgO6 octahedra that share corners with two equivalent S(2)O4 tetrahedra. Both Mg(2)-O(9) bond lengths are 2.06 Å. All Mg(2)-O(2) bond lengths are 2.04 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded to one O(5), one O(7), and two equivalent O(8) atoms to form SO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles are 18°. The S(1)-O(5) bond length is 1.52 Å. The S(1)-O(7) bond length is 1.47 Å. Both S(1)-O(8) bond lengths are 1.48 Å. In the second S site, S(2) is bonded to one O(4), one O(9), and two equivalent O(3) atoms to form SO4 tetrahedra that share  a cornercorner with one Mg(2)O6 octahedra. The corner-sharing octahedral tilt angles are 38°. The S(2)-O(4) bond length is 1.48 Å. The S(2)-O(9) bond length is 1.52 Å. Both S(2)-O(3) bond lengths are 1.48 Å. There are nine inequivalent O sites. In the first O site, O(5) is bonded in a distorted bent 150 degrees geometry to two equivalent K(1), one Mg(1), and one S(1) atom. In the second O site, O(6) is bonded in a distorted single-bond geometry to two equivalent K(1) and one Mg(1) atom. In the third O site, O(7) is bonded in a distorted trigonal planar geometry to two equivalent K(1) and one S(1) atom. In the fourth O site, O(8) is bonded in a distorted single-bond geometry to one K(1) and one S(1) atom. In the fifth O site, O(9) is bonded in a distorted bent 150 degrees geometry to two equivalent K(1), one Mg(2), and one S(2) atom. In the sixth O site, O(1) is bonded in a single-bond geometry to two equivalent K(1) and one Mg(1) atom. In the seventh O site, O(2) is bonded in a bent 120 degrees geometry to one K(1) and one Mg(2) atom. In the eighth O site, O(3) is bonded in a distorted single-bond geometry to one K(1) and one S(2) atom. In the ninth O site, O(4) is bonded in a distorted single-bond geometry to two equivalent K(1) and one S(2) atom.