NiH2SeO5 crystallizes in the monoclinic C2/c space group. Ni(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NiO6 octahedra that share corners with two equivalent Ni(1)O6 octahedra and corners with four equivalent Se(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 56°. H(1) is bonded in a single-bond geometry to one O(1) and one O(3) atom. Se(1) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form SeO4 tetrahedra that share corners with four equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-56°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted water-like geometry to two equivalent Ni(1) and two equivalent H(1) atoms. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Ni(1) and one Se(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Ni(1), one H(1), and one Se(1) atom.
NiH2SeO5 crystallizes in the monoclinic C2/c space group. Ni(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NiO6 octahedra that share corners with two equivalent Ni(1)O6 octahedra and corners with four equivalent Se(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 56°. Both Ni(1)-O(1) bond lengths are 2.12 Å. Both Ni(1)-O(2) bond lengths are 2.01 Å. Both Ni(1)-O(3) bond lengths are 2.03 Å. H(1) is bonded in a single-bond geometry to one O(1) and one O(3) atom. The H(1)-O(1) bond length is 1.00 Å. The H(1)-O(3) bond length is 1.70 Å. Se(1) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form SeO4 tetrahedra that share corners with four equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-56°. Both Se(1)-O(2) bond lengths are 1.65 Å. Both Se(1)-O(3) bond lengths are 1.67 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted water-like geometry to two equivalent Ni(1) and two equivalent H(1) atoms. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Ni(1) and one Se(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Ni(1), one H(1), and one Se(1) atom.