MnCu(SeO3)2 crystallizes in the monoclinic P2_1/c space group. Mn(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MnO6 octahedra that share corners with six equivalent Cu(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-56°. Cu(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CuO6 octahedra that share corners with six equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-56°. Se(1) is bonded in a trigonal non-coplanar geometry to one O(1), one O(2), and one O(3) atom. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Mn(1), one Cu(1), and one Se(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mn(1), one Cu(1), and one Se(1) atom. In the third O site, O(3) is bonded in a trigonal non-coplanar geometry to one Mn(1), one Cu(1), and one Se(1) atom.
MnCu(SeO3)2 crystallizes in the monoclinic P2_1/c space group. Mn(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MnO6 octahedra that share corners with six equivalent Cu(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-56°. Both Mn(1)-O(1) bond lengths are 2.06 Å. Both Mn(1)-O(2) bond lengths are 2.44 Å. Both Mn(1)-O(3) bond lengths are 2.29 Å. Cu(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CuO6 octahedra that share corners with six equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-56°. Both Cu(1)-O(1) bond lengths are 2.48 Å. Both Cu(1)-O(2) bond lengths are 2.06 Å. Both Cu(1)-O(3) bond lengths are 2.05 Å. Se(1) is bonded in a trigonal non-coplanar geometry to one O(1), one O(2), and one O(3) atom. The Se(1)-O(1) bond length is 1.73 Å. The Se(1)-O(2) bond length is 1.76 Å. The Se(1)-O(3) bond length is 1.77 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Mn(1), one Cu(1), and one Se(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mn(1), one Cu(1), and one Se(1) atom. In the third O site, O(3) is bonded in a trigonal non-coplanar geometry to one Mn(1), one Cu(1), and one Se(1) atom.