Nb2NiZn2O8 crystallizes in the monoclinic C2/c space group. Nb(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form distorted NbO6 octahedra that share corners with four equivalent Ni(1)O6 octahedra, corners with five equivalent Zn(1)O4 tetrahedra, and edges with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-57°. Ni(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form NiO6 octahedra that share corners with eight equivalent Nb(1)O6 octahedra and edges with two equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-57°. Zn(1) is bonded to one O(3) and three equivalent O(4) atoms to form distorted ZnO4 tetrahedra that share corners with five equivalent Nb(1)O6 octahedra, corners with four equivalent Zn(1)O4 tetrahedra, and  an edgeedge with one Zn(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 54-79°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to two equivalent Nb(1) and one Ni(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Nb(1) and two equivalent Ni(1) atoms. In the third O site, O(3) is bonded in a 3-coordinate geometry to two equivalent Nb(1) and one Zn(1) atom. In the fourth O site, O(4) is bonded to one Nb(1) and three equivalent Zn(1) atoms to form a mixture of corner and edge-sharing ONbZn3 trigonal pyramids.
Nb2NiZn2O8 crystallizes in the monoclinic C2/c space group. Nb(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form distorted NbO6 octahedra that share corners with four equivalent Ni(1)O6 octahedra, corners with five equivalent Zn(1)O4 tetrahedra, and edges with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-57°. The Nb(1)-O(2) bond length is 1.85 Å. The Nb(1)-O(4) bond length is 2.04 Å. There is one shorter (2.01 Å) and one longer (2.03 Å) Nb(1)-O(1) bond length. There is one shorter (2.02 Å) and one longer (2.30 Å) Nb(1)-O(3) bond length. Ni(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form NiO6 octahedra that share corners with eight equivalent Nb(1)O6 octahedra and edges with two equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-57°. Both Ni(1)-O(1) bond lengths are 2.16 Å. All Ni(1)-O(2) bond lengths are 2.09 Å. Zn(1) is bonded to one O(3) and three equivalent O(4) atoms to form distorted ZnO4 tetrahedra that share corners with five equivalent Nb(1)O6 octahedra, corners with four equivalent Zn(1)O4 tetrahedra, and  an edgeedge with one Zn(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 54-79°. The Zn(1)-O(3) bond length is 1.99 Å. There are a spread of Zn(1)-O(4) bond distances ranging from 1.98-2.09 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to two equivalent Nb(1) and one Ni(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Nb(1) and two equivalent Ni(1) atoms. In the third O site, O(3) is bonded in a 3-coordinate geometry to two equivalent Nb(1) and one Zn(1) atom. In the fourth O site, O(4) is bonded to one Nb(1) and three equivalent Zn(1) atoms to form a mixture of corner and edge-sharing ONbZn3 trigonal pyramids.