Hf2ON2 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Hf sites. In the first Hf site, Hf(1) is bonded in a 7-coordinate geometry to two equivalent N(2), three equivalent N(1), and two equivalent O(1) atoms. In the second Hf site, Hf(2) is bonded in a 7-coordinate geometry to two equivalent N(2), three equivalent N(1), and two equivalent O(1) atoms. There are two inequivalent N sites. In the first N site, N(1) is bonded to three equivalent Hf(1) and three equivalent Hf(2) atoms to form NHf6 octahedra that share corners with six equivalent N(2)Hf4 tetrahedra, corners with six equivalent O(1)Hf4 tetrahedra, edges with six equivalent N(1)Hf6 octahedra, edges with three equivalent N(2)Hf4 tetrahedra, and edges with three equivalent O(1)Hf4 tetrahedra. In the second N site, N(2) is bonded to two equivalent Hf(1) and two equivalent Hf(2) atoms to form NHf4 tetrahedra that share corners with six equivalent N(1)Hf6 octahedra, corners with two equivalent N(2)Hf4 tetrahedra, corners with four equivalent O(1)Hf4 tetrahedra, edges with three equivalent N(1)Hf6 octahedra,  an edgeedge with one N(2)Hf4 tetrahedra, and edges with two equivalent O(1)Hf4 tetrahedra. The corner-sharing octahedral tilt angles range from 10-57°. O(1) is bonded to two equivalent Hf(1) and two equivalent Hf(2) atoms to form distorted OHf4 tetrahedra that share corners with six equivalent N(1)Hf6 octahedra, corners with two equivalent O(1)Hf4 tetrahedra, corners with four equivalent N(2)Hf4 tetrahedra, edges with three equivalent N(1)Hf6 octahedra,  an edgeedge with one O(1)Hf4 tetrahedra, and edges with two equivalent N(2)Hf4 tetrahedra. The corner-sharing octahedral tilt angles range from 18-58°.
Hf2ON2 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Hf sites. In the first Hf site, Hf(1) is bonded in a 7-coordinate geometry to two equivalent N(2), three equivalent N(1), and two equivalent O(1) atoms. There is one shorter (2.07 Å) and one longer (2.20 Å) Hf(1)-N(2) bond length. There are a spread of Hf(1)-N(1) bond distances ranging from 2.39-2.50 Å. There is one shorter (2.09 Å) and one longer (2.10 Å) Hf(1)-O(1) bond length. In the second Hf site, Hf(2) is bonded in a 7-coordinate geometry to two equivalent N(2), three equivalent N(1), and two equivalent O(1) atoms. There is one shorter (2.06 Å) and one longer (2.08 Å) Hf(2)-N(2) bond length. There are a spread of Hf(2)-N(1) bond distances ranging from 2.30-2.49 Å. There is one shorter (2.09 Å) and one longer (2.47 Å) Hf(2)-O(1) bond length. There are two inequivalent N sites. In the first N site, N(1) is bonded to three equivalent Hf(1) and three equivalent Hf(2) atoms to form NHf6 octahedra that share corners with six equivalent N(2)Hf4 tetrahedra, corners with six equivalent O(1)Hf4 tetrahedra, edges with six equivalent N(1)Hf6 octahedra, edges with three equivalent N(2)Hf4 tetrahedra, and edges with three equivalent O(1)Hf4 tetrahedra. In the second N site, N(2) is bonded to two equivalent Hf(1) and two equivalent Hf(2) atoms to form NHf4 tetrahedra that share corners with six equivalent N(1)Hf6 octahedra, corners with two equivalent N(2)Hf4 tetrahedra, corners with four equivalent O(1)Hf4 tetrahedra, edges with three equivalent N(1)Hf6 octahedra,  an edgeedge with one N(2)Hf4 tetrahedra, and edges with two equivalent O(1)Hf4 tetrahedra. The corner-sharing octahedral tilt angles range from 10-57°. O(1) is bonded to two equivalent Hf(1) and two equivalent Hf(2) atoms to form distorted OHf4 tetrahedra that share corners with six equivalent N(1)Hf6 octahedra, corners with two equivalent O(1)Hf4 tetrahedra, corners with four equivalent N(2)Hf4 tetrahedra, edges with three equivalent N(1)Hf6 octahedra,  an edgeedge with one O(1)Hf4 tetrahedra, and edges with two equivalent N(2)Hf4 tetrahedra. The corner-sharing octahedral tilt angles range from 18-58°.