Hf2ON2 is Ilmenite-like structured and crystallizes in the monoclinic C2 space group. There are four inequivalent Hf sites. In the first Hf site, Hf(1) is bonded to one N(2), one N(4), two equivalent N(1), one O(1), and one O(2) atom to form a mixture of distorted corner and edge-sharing HfN4O2 octahedra. The corner-sharing octahedral tilt angles range from 43-66°. In the second Hf site, Hf(2) is bonded in a 6-coordinate geometry to one N(2), one N(4), two equivalent N(3), one O(1), and one O(3) atom. In the third Hf site, Hf(3) is bonded to one N(2), one N(4), two equivalent N(1), one O(1), and one O(2) atom to form a mixture of distorted corner, edge, and face-sharing HfN4O2 octahedra. The corner-sharing octahedral tilt angles range from 43-68°. In the fourth Hf site, Hf(4) is bonded to one N(2), one N(4), two equivalent N(3), one O(1), and one O(3) atom to form a mixture of distorted corner and face-sharing HfN4O2 octahedra. The corner-sharing octahedral tilt angles range from 47-68°. There are four inequivalent N sites. In the first N site, N(1) is bonded in a distorted see-saw-like geometry to two equivalent Hf(1) and two equivalent Hf(3) atoms. In the second N site, N(2) is bonded in a distorted see-saw-like geometry to one Hf(1), one Hf(2), one Hf(3), and one Hf(4) atom. In the third N site, N(3) is bonded to two equivalent Hf(2) and two equivalent Hf(4) atoms to form distorted NHf4 trigonal pyramids that share corners with two equivalent N(3)Hf4 trigonal pyramids, corners with two equivalent O(3)Hf4 trigonal pyramids, corners with four equivalent N(4)Hf4 trigonal pyramids,  an edgeedge with one N(3)Hf4 trigonal pyramid, and  an edgeedge with one O(3)Hf4 trigonal pyramid. In the fourth N site, N(4) is bonded to one Hf(1), one Hf(2), one Hf(3), and one Hf(4) atom to form distorted NHf4 trigonal pyramids that share corners with four equivalent N(3)Hf4 trigonal pyramids,  an edgeedge with one O(2)Hf4 trigonal pyramid, and  an edgeedge with one O(3)Hf4 trigonal pyramid. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Hf(1), one Hf(2), one Hf(3), and one Hf(4) atom. In the second O site, O(2) is bonded to two equivalent Hf(1) and two equivalent Hf(3) atoms to form distorted OHf4 trigonal pyramids that share edges with two equivalent N(4)Hf4 trigonal pyramids. In the third O site, O(3) is bonded to two equivalent Hf(2) and two equivalent Hf(4) atoms to form distorted OHf4 trigonal pyramids that share corners with four equivalent N(3)Hf4 trigonal pyramids, edges with two equivalent N(3)Hf4 trigonal pyramids, and edges with two equivalent N(4)Hf4 trigonal pyramids.
Hf2ON2 is Ilmenite-like structured and crystallizes in the monoclinic C2 space group. There are four inequivalent Hf sites. In the first Hf site, Hf(1) is bonded to one N(2), one N(4), two equivalent N(1), one O(1), and one O(2) atom to form a mixture of distorted corner and edge-sharing HfN4O2 octahedra. The corner-sharing octahedral tilt angles range from 43-66°. The Hf(1)-N(2) bond length is 2.37 Å. The Hf(1)-N(4) bond length is 2.19 Å. There is one shorter (2.08 Å) and one longer (2.17 Å) Hf(1)-N(1) bond length. The Hf(1)-O(1) bond length is 2.24 Å. The Hf(1)-O(2) bond length is 2.07 Å. In the second Hf site, Hf(2) is bonded in a 6-coordinate geometry to one N(2), one N(4), two equivalent N(3), one O(1), and one O(3) atom. The Hf(2)-N(2) bond length is 2.17 Å. The Hf(2)-N(4) bond length is 2.22 Å. There is one shorter (2.03 Å) and one longer (2.15 Å) Hf(2)-N(3) bond length. The Hf(2)-O(1) bond length is 2.52 Å. The Hf(2)-O(3) bond length is 2.16 Å. In the third Hf site, Hf(3) is bonded to one N(2), one N(4), two equivalent N(1), one O(1), and one O(2) atom to form a mixture of distorted corner, edge, and face-sharing HfN4O2 octahedra. The corner-sharing octahedral tilt angles range from 43-68°. The Hf(3)-N(2) bond length is 2.03 Å. The Hf(3)-N(4) bond length is 2.16 Å. There is one shorter (2.15 Å) and one longer (2.28 Å) Hf(3)-N(1) bond length. The Hf(3)-O(1) bond length is 2.16 Å. The Hf(3)-O(2) bond length is 2.41 Å. In the fourth Hf site, Hf(4) is bonded to one N(2), one N(4), two equivalent N(3), one O(1), and one O(3) atom to form a mixture of distorted corner and face-sharing HfN4O2 octahedra. The corner-sharing octahedral tilt angles range from 47-68°. The Hf(4)-N(2) bond length is 2.16 Å. The Hf(4)-N(4) bond length is 2.11 Å. There is one shorter (2.22 Å) and one longer (2.27 Å) Hf(4)-N(3) bond length. The Hf(4)-O(1) bond length is 2.07 Å. The Hf(4)-O(3) bond length is 2.31 Å. There are four inequivalent N sites. In the first N site, N(1) is bonded in a distorted see-saw-like geometry to two equivalent Hf(1) and two equivalent Hf(3) atoms. In the second N site, N(2) is bonded in a distorted see-saw-like geometry to one Hf(1), one Hf(2), one Hf(3), and one Hf(4) atom. In the third N site, N(3) is bonded to two equivalent Hf(2) and two equivalent Hf(4) atoms to form distorted NHf4 trigonal pyramids that share corners with two equivalent N(3)Hf4 trigonal pyramids, corners with two equivalent O(3)Hf4 trigonal pyramids, corners with four equivalent N(4)Hf4 trigonal pyramids,  an edgeedge with one N(3)Hf4 trigonal pyramid, and  an edgeedge with one O(3)Hf4 trigonal pyramid. In the fourth N site, N(4) is bonded to one Hf(1), one Hf(2), one Hf(3), and one Hf(4) atom to form distorted NHf4 trigonal pyramids that share corners with four equivalent N(3)Hf4 trigonal pyramids,  an edgeedge with one O(2)Hf4 trigonal pyramid, and  an edgeedge with one O(3)Hf4 trigonal pyramid. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Hf(1), one Hf(2), one Hf(3), and one Hf(4) atom. In the second O site, O(2) is bonded to two equivalent Hf(1) and two equivalent Hf(3) atoms to form distorted OHf4 trigonal pyramids that share edges with two equivalent N(4)Hf4 trigonal pyramids. In the third O site, O(3) is bonded to two equivalent Hf(2) and two equivalent Hf(4) atoms to form distorted OHf4 trigonal pyramids that share corners with four equivalent N(3)Hf4 trigonal pyramids, edges with two equivalent N(3)Hf4 trigonal pyramids, and edges with two equivalent N(4)Hf4 trigonal pyramids.