MgZn4(Se2O5)4 crystallizes in the monoclinic P2 space group. Mg(1) is bonded in a 6-coordinate geometry to two equivalent Se(1), two equivalent O(11), and two equivalent O(6) atoms. There are four inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to two equivalent O(10), two equivalent O(12), and two equivalent O(6) atoms to form distorted edge-sharing ZnO6 pentagonal pyramids. In the second Zn site, Zn(2) is bonded to two equivalent O(11), two equivalent O(5), and two equivalent O(9) atoms to form distorted edge-sharing ZnO6 pentagonal pyramids. In the third Zn site, Zn(3) is bonded to two equivalent O(10), two equivalent O(12), and two equivalent O(8) atoms to form distorted edge-sharing ZnO6 pentagonal pyramids. In the fourth Zn site, Zn(4) is bonded to two equivalent O(11), two equivalent O(7), and two equivalent O(9) atoms to form distorted edge-sharing ZnO6 octahedra. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded in a 3-coordinate geometry to one Mg(1), one O(12), one O(2), and one O(5) atom. In the second Se site, Se(2) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(11), one O(5), and one O(6) atom. In the third Se site, Se(3) is bonded in a distorted trigonal non-coplanar geometry to one O(10), one O(4), and one O(7) atom. In the fourth Se site, Se(4) is bonded in a distorted trigonal non-coplanar geometry to one O(3), one O(8), and one O(9) atom. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to two equivalent Se(2) atoms. In the second O site, O(2) is bonded in a bent 120 degrees geometry to two equivalent Se(1) atoms. In the third O site, O(3) is bonded in a bent 120 degrees geometry to two equivalent Se(4) atoms. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to two equivalent Se(3) atoms. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Zn(2), one Se(1), and one Se(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Mg(1), one Zn(1), and one Se(2) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Zn(4) and one Se(3) atom. In the eighth O site, O(8) is bonded in a bent 120 degrees geometry to one Zn(3) and one Se(4) atom. In the ninth O site, O(9) is bonded in a distorted trigonal non-coplanar geometry to one Zn(2), one Zn(4), and one Se(4) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Zn(1), one Zn(3), and one Se(3) atom. In the eleventh O site, O(11) is bonded to one Mg(1), one Zn(2), one Zn(4), and one Se(2) atom to form a mixture of corner and edge-sharing OMgZn2Se tetrahedra. In the twelfth O site, O(12) is bonded in a trigonal non-coplanar geometry to one Zn(1), one Zn(3), and one Se(1) atom.
MgZn4(Se2O5)4 crystallizes in the monoclinic P2 space group. Mg(1) is bonded in a 6-coordinate geometry to two equivalent Se(1), two equivalent O(11), and two equivalent O(6) atoms. Both Mg(1)-Se(1) bond lengths are 2.79 Å. Both Mg(1)-O(11) bond lengths are 2.20 Å. Both Mg(1)-O(6) bond lengths are 2.12 Å. There are four inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to two equivalent O(10), two equivalent O(12), and two equivalent O(6) atoms to form distorted edge-sharing ZnO6 pentagonal pyramids. Both Zn(1)-O(10) bond lengths are 2.12 Å. Both Zn(1)-O(12) bond lengths are 2.01 Å. Both Zn(1)-O(6) bond lengths are 2.32 Å. In the second Zn site, Zn(2) is bonded to two equivalent O(11), two equivalent O(5), and two equivalent O(9) atoms to form distorted edge-sharing ZnO6 pentagonal pyramids. Both Zn(2)-O(11) bond lengths are 2.25 Å. Both Zn(2)-O(5) bond lengths are 2.14 Å. Both Zn(2)-O(9) bond lengths are 2.18 Å. In the third Zn site, Zn(3) is bonded to two equivalent O(10), two equivalent O(12), and two equivalent O(8) atoms to form distorted edge-sharing ZnO6 pentagonal pyramids. Both Zn(3)-O(10) bond lengths are 2.38 Å. Both Zn(3)-O(12) bond lengths are 2.09 Å. Both Zn(3)-O(8) bond lengths are 2.13 Å. In the fourth Zn site, Zn(4) is bonded to two equivalent O(11), two equivalent O(7), and two equivalent O(9) atoms to form distorted edge-sharing ZnO6 octahedra. Both Zn(4)-O(11) bond lengths are 2.16 Å. Both Zn(4)-O(7) bond lengths are 2.03 Å. Both Zn(4)-O(9) bond lengths are 2.25 Å. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded in a 3-coordinate geometry to one Mg(1), one O(12), one O(2), and one O(5) atom. The Se(1)-O(12) bond length is 1.84 Å. The Se(1)-O(2) bond length is 1.90 Å. The Se(1)-O(5) bond length is 1.77 Å. In the second Se site, Se(2) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(11), one O(5), and one O(6) atom. The Se(2)-O(1) bond length is 1.90 Å. The Se(2)-O(11) bond length is 1.80 Å. The Se(2)-O(5) bond length is 2.33 Å. The Se(2)-O(6) bond length is 1.71 Å. In the third Se site, Se(3) is bonded in a distorted trigonal non-coplanar geometry to one O(10), one O(4), and one O(7) atom. The Se(3)-O(10) bond length is 1.69 Å. The Se(3)-O(4) bond length is 1.89 Å. The Se(3)-O(7) bond length is 1.71 Å. In the fourth Se site, Se(4) is bonded in a distorted trigonal non-coplanar geometry to one O(3), one O(8), and one O(9) atom. The Se(4)-O(3) bond length is 1.88 Å. The Se(4)-O(8) bond length is 1.70 Å. The Se(4)-O(9) bond length is 1.73 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to two equivalent Se(2) atoms. In the second O site, O(2) is bonded in a bent 120 degrees geometry to two equivalent Se(1) atoms. In the third O site, O(3) is bonded in a bent 120 degrees geometry to two equivalent Se(4) atoms. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to two equivalent Se(3) atoms. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Zn(2), one Se(1), and one Se(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Mg(1), one Zn(1), and one Se(2) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Zn(4) and one Se(3) atom. In the eighth O site, O(8) is bonded in a bent 120 degrees geometry to one Zn(3) and one Se(4) atom. In the ninth O site, O(9) is bonded in a distorted trigonal non-coplanar geometry to one Zn(2), one Zn(4), and one Se(4) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Zn(1), one Zn(3), and one Se(3) atom. In the eleventh O site, O(11) is bonded to one Mg(1), one Zn(2), one Zn(4), and one Se(2) atom to form a mixture of corner and edge-sharing OMgZn2Se tetrahedra. In the twelfth O site, O(12) is bonded in a trigonal non-coplanar geometry to one Zn(1), one Zn(3), and one Se(1) atom.