K2Mg(SeO7)2 crystallizes in the monoclinic P2_1/c space group. K(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(5), one O(6), two equivalent O(3), and two equivalent O(4) atoms. Mg(1) is bonded in a distorted octahedral geometry to two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms. Se(1) is bonded in a tetrahedral geometry to one O(1), one O(2), one O(3), and one O(4) atom. There are seven inequivalent O sites. In the first O site, O(7) is bonded in a single-bond geometry to one Mg(1) atom. In the second O site, O(1) is bonded in a distorted water-like geometry to one K(1) and one Se(1) atom. In the third O site, O(2) is bonded in a distorted water-like geometry to one K(1) and one Se(1) atom. In the fourth O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to two equivalent K(1) and one Se(1) atom. In the fifth O site, O(4) is bonded in a distorted single-bond geometry to two equivalent K(1) and one Se(1) atom. In the sixth O site, O(5) is bonded in a bent 150 degrees geometry to one K(1) and one Mg(1) atom. In the seventh O site, O(6) is bonded in a 2-coordinate geometry to one K(1) and one Mg(1) atom.
K2Mg(SeO7)2 crystallizes in the monoclinic P2_1/c space group. K(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(5), one O(6), two equivalent O(3), and two equivalent O(4) atoms. The K(1)-O(1) bond length is 2.80 Å. The K(1)-O(2) bond length is 2.82 Å. The K(1)-O(5) bond length is 2.82 Å. The K(1)-O(6) bond length is 2.78 Å. There is one shorter (2.74 Å) and one longer (2.87 Å) K(1)-O(3) bond length. There is one shorter (3.15 Å) and one longer (3.27 Å) K(1)-O(4) bond length. Mg(1) is bonded in a distorted octahedral geometry to two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms. Both Mg(1)-O(5) bond lengths are 2.03 Å. Both Mg(1)-O(6) bond lengths are 2.08 Å. Both Mg(1)-O(7) bond lengths are 2.19 Å. Se(1) is bonded in a tetrahedral geometry to one O(1), one O(2), one O(3), and one O(4) atom. The Se(1)-O(1) bond length is 1.70 Å. The Se(1)-O(2) bond length is 1.71 Å. The Se(1)-O(3) bond length is 1.66 Å. The Se(1)-O(4) bond length is 1.67 Å. There are seven inequivalent O sites. In the first O site, O(7) is bonded in a single-bond geometry to one Mg(1) atom. In the second O site, O(1) is bonded in a distorted water-like geometry to one K(1) and one Se(1) atom. In the third O site, O(2) is bonded in a distorted water-like geometry to one K(1) and one Se(1) atom. In the fourth O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to two equivalent K(1) and one Se(1) atom. In the fifth O site, O(4) is bonded in a distorted single-bond geometry to two equivalent K(1) and one Se(1) atom. In the sixth O site, O(5) is bonded in a bent 150 degrees geometry to one K(1) and one Mg(1) atom. In the seventh O site, O(6) is bonded in a 2-coordinate geometry to one K(1) and one Mg(1) atom.