KMn(SeO4)2 crystallizes in the triclinic P-1 space group. K(1) is bonded in a 10-coordinate geometry to two equivalent O(1), two equivalent O(4), and six equivalent O(3) atoms. Mn(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form MnO6 octahedra that share corners with six equivalent Se(1)O4 tetrahedra. Se(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SeO4 tetrahedra that share corners with three equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-49°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one K(1), one Mn(1), and one Se(1) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Mn(1) and one Se(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to three equivalent K(1) and one Se(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one K(1), one Mn(1), and one Se(1) atom.
KMn(SeO4)2 crystallizes in the triclinic P-1 space group. K(1) is bonded in a 10-coordinate geometry to two equivalent O(1), two equivalent O(4), and six equivalent O(3) atoms. Both K(1)-O(1) bond lengths are 2.91 Å. Both K(1)-O(4) bond lengths are 2.93 Å. There are a spread of K(1)-O(3) bond distances ranging from 2.85-3.34 Å. Mn(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form MnO6 octahedra that share corners with six equivalent Se(1)O4 tetrahedra. Both Mn(1)-O(1) bond lengths are 1.97 Å. Both Mn(1)-O(2) bond lengths are 1.95 Å. Both Mn(1)-O(4) bond lengths are 2.24 Å. Se(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SeO4 tetrahedra that share corners with three equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-49°. The Se(1)-O(1) bond length is 1.71 Å. The Se(1)-O(2) bond length is 1.69 Å. The Se(1)-O(3) bond length is 1.64 Å. The Se(1)-O(4) bond length is 1.67 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one K(1), one Mn(1), and one Se(1) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Mn(1) and one Se(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to three equivalent K(1) and one Se(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one K(1), one Mn(1), and one Se(1) atom.