ZnSeO5 crystallizes in the monoclinic P2_1/c space group. Zn(1) is bonded to one O(1), one O(3), one O(4), one O(5), and two equivalent O(2) atoms to form distorted ZnO6 octahedra that share corners with five equivalent Se(1)O4 tetrahedra and  an edgeedge with one Zn(1)O6 octahedra. Se(1) is bonded to one O(1), one O(2), one O(3), and one O(5) atom to form SeO4 tetrahedra that share corners with five equivalent Zn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 26-60°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Zn(1) and one Se(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Zn(1) and one Se(1) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Zn(1) and one Se(1) atom. In the fourth O site, O(4) is bonded in a single-bond geometry to one Zn(1) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Zn(1) and one Se(1) atom.
ZnSeO5 crystallizes in the monoclinic P2_1/c space group. Zn(1) is bonded to one O(1), one O(3), one O(4), one O(5), and two equivalent O(2) atoms to form distorted ZnO6 octahedra that share corners with five equivalent Se(1)O4 tetrahedra and  an edgeedge with one Zn(1)O6 octahedra. The Zn(1)-O(1) bond length is 2.00 Å. The Zn(1)-O(3) bond length is 2.11 Å. The Zn(1)-O(4) bond length is 2.01 Å. The Zn(1)-O(5) bond length is 2.26 Å. There is one shorter (2.14 Å) and one longer (2.41 Å) Zn(1)-O(2) bond length. Se(1) is bonded to one O(1), one O(2), one O(3), and one O(5) atom to form SeO4 tetrahedra that share corners with five equivalent Zn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 26-60°. The Se(1)-O(1) bond length is 1.67 Å. The Se(1)-O(2) bond length is 1.69 Å. The Se(1)-O(3) bond length is 1.69 Å. The Se(1)-O(5) bond length is 1.68 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Zn(1) and one Se(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Zn(1) and one Se(1) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Zn(1) and one Se(1) atom. In the fourth O site, O(4) is bonded in a single-bond geometry to one Zn(1) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Zn(1) and one Se(1) atom.