NbO2 crystallizes in the monoclinic C2/m space group. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form a mixture of distorted edge and corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles are 36°. In the second Nb site, Nb(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), and three equivalent O(4) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Nb(2) and two equivalent Nb(1) atoms. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Nb(2) and two equivalent Nb(1) atoms. In the third O site, O(3) is bonded in a linear geometry to one Nb(1) and one Nb(2) atom. In the fourth O site, O(4) is bonded to one Nb(1) and three equivalent Nb(2) atoms to form a mixture of distorted edge and corner-sharing ONb4 trigonal pyramids.
NbO2 crystallizes in the monoclinic C2/m space group. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form a mixture of distorted edge and corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles are 36°. The Nb(1)-O(3) bond length is 2.12 Å. The Nb(1)-O(4) bond length is 2.35 Å. There is one shorter (2.07 Å) and one longer (2.12 Å) Nb(1)-O(1) bond length. Both Nb(1)-O(2) bond lengths are 2.05 Å. In the second Nb site, Nb(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), and three equivalent O(4) atoms. The Nb(2)-O(1) bond length is 1.94 Å. The Nb(2)-O(2) bond length is 2.12 Å. The Nb(2)-O(3) bond length is 1.80 Å. There are two shorter (2.05 Å) and one longer (2.49 Å) Nb(2)-O(4) bond length. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Nb(2) and two equivalent Nb(1) atoms. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Nb(2) and two equivalent Nb(1) atoms. In the third O site, O(3) is bonded in a linear geometry to one Nb(1) and one Nb(2) atom. In the fourth O site, O(4) is bonded to one Nb(1) and three equivalent Nb(2) atoms to form a mixture of distorted edge and corner-sharing ONb4 trigonal pyramids.