The compound described by Hf2ON2 crystallizes in the monoclinic C2/m space group. There are three inequivalent Hf sites. In the first Hf site, Hf(1) is bonded to one N(2), one N(3), two equivalent N(1), and two equivalent O(2) atoms to form a mixture of corner and edge-sharing HfN4O2 octahedra. The corner-sharing octahedra are not tilted. In the second Hf site, Hf(2) is bonded in a 7-coordinate geometry to two equivalent N(1), two equivalent N(3), and three equivalent O(1) atoms. In the third Hf site, Hf(3) is bonded in a 7-coordinate geometry to two equivalent N(3), three equivalent N(2), one O(1), and one O(2) atom. There are three inequivalent N sites. In the first N site, N(1) is bonded to two equivalent Hf(1) and two equivalent Hf(2) atoms to form distorted NHf4 tetrahedra that share corners with two equivalent O(2)Hf6 octahedra, corners with two equivalent N(1)Hf4 tetrahedra, corners with two equivalent N(2)Hf4 tetrahedra, corners with two equivalent N(3)Hf5 trigonal bipyramids,  an edgeedge with one O(2)Hf6 octahedra,  an edgeedge with one N(1)Hf4 tetrahedra, and edges with two equivalent N(3)Hf5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 11°. In the second N site, N(2) is bonded to one Hf(1) and three equivalent Hf(3) atoms to form NHf4 tetrahedra that share  a cornercorner with one O(2)Hf6 octahedra, corners with two equivalent N(1)Hf4 tetrahedra, corners with two equivalent N(2)Hf4 tetrahedra, corners with five equivalent N(3)Hf5 trigonal bipyramids, edges with two equivalent O(2)Hf6 octahedra, edges with two equivalent N(2)Hf4 tetrahedra, and  an edgeedge with one N(3)Hf5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 45°. In the third N site, N(3) is bonded to one Hf(1), two equivalent Hf(2), and two equivalent Hf(3) atoms to form distorted NHf5 trigonal bipyramids that share corners with two equivalent N(1)Hf4 tetrahedra, corners with five equivalent N(2)Hf4 tetrahedra, edges with two equivalent O(2)Hf6 octahedra,  an edgeedge with one N(2)Hf4 tetrahedra, edges with two equivalent N(1)Hf4 tetrahedra, and edges with two equivalent N(3)Hf5 trigonal bipyramids. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Hf(3) and three equivalent Hf(2) atoms. In the second O site, O(2) is bonded to two equivalent Hf(3) and four equivalent Hf(1) atoms to form OHf6 octahedra that share corners with two equivalent N(2)Hf4 tetrahedra, corners with four equivalent N(1)Hf4 tetrahedra, edges with two equivalent O(2)Hf6 octahedra, edges with two equivalent N(1)Hf4 tetrahedra, edges with four equivalent N(2)Hf4 tetrahedra, and edges with four equivalent N(3)Hf5 trigonal bipyramids. is represented by the CIF file [CIF]
data_Hf2N2O
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.042
_cell_length_b   7.042
_cell_length_c   8.177
_cell_angle_alpha   79.831
_cell_angle_beta   79.831
_cell_angle_gamma   26.744
_symmetry_Int_Tables_number   1
_cell_volume   179.443
_cell_formula_units_Z   3
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Hf  Hf0  1  0.970  0.970  0.809  1.0
  Hf  Hf1  1  0.371  0.371  0.475  1.0
  Hf  Hf2  1  0.304  0.304  0.132  1.0
  Hf  Hf3  1  0.696  0.696  0.868  1.0
  Hf  Hf4  1  0.629  0.629  0.525  1.0
  Hf  Hf5  1  0.030  0.030  0.191  1.0
  N  N6  1  0.465  0.465  0.657  1.0
  N  N7  1  0.828  0.828  0.964  1.0
  N  N8  1  0.873  0.873  0.285  1.0
  N  N9  1  0.127  0.127  0.715  1.0
  N  N10  1  0.172  0.172  0.036  1.0
  N  N11  1  0.535  0.535  0.343  1.0
  O  O12  1  0.790  0.790  0.617  1.0
  O  O13  1  0.210  0.210  0.383  1.0
  O  O14  1  0.500  0.500  0.000  1.0
[/CIF]
.
The compound described by Hf2ON2 crystallizes in the monoclinic C2/m space group. There are three inequivalent Hf sites. In the first Hf site, Hf(1) is bonded to one N(2), one N(3), two equivalent N(1), and two equivalent O(2) atoms to form a mixture of corner and edge-sharing HfN4O2 octahedra. The corner-sharing octahedra are not tilted. In the second Hf site, Hf(2) is bonded in a 7-coordinate geometry to two equivalent N(1), two equivalent N(3), and three equivalent O(1) atoms. In the third Hf site, Hf(3) is bonded in a 7-coordinate geometry to two equivalent N(3), three equivalent N(2), one O(1), and one O(2) atom. There are three inequivalent N sites. In the first N site, N(1) is bonded to two equivalent Hf(1) and two equivalent Hf(2) atoms to form distorted NHf4 tetrahedra that share corners with two equivalent O(2)Hf6 octahedra, corners with two equivalent N(1)Hf4 tetrahedra, corners with two equivalent N(2)Hf4 tetrahedra, corners with two equivalent N(3)Hf5 trigonal bipyramids,  an edgeedge with one O(2)Hf6 octahedra,  an edgeedge with one N(1)Hf4 tetrahedra, and edges with two equivalent N(3)Hf5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 11°. In the second N site, N(2) is bonded to one Hf(1) and three equivalent Hf(3) atoms to form NHf4 tetrahedra that share  a cornercorner with one O(2)Hf6 octahedra, corners with two equivalent N(1)Hf4 tetrahedra, corners with two equivalent N(2)Hf4 tetrahedra, corners with five equivalent N(3)Hf5 trigonal bipyramids, edges with two equivalent O(2)Hf6 octahedra, edges with two equivalent N(2)Hf4 tetrahedra, and  an edgeedge with one N(3)Hf5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 45°. In the third N site, N(3) is bonded to one Hf(1), two equivalent Hf(2), and two equivalent Hf(3) atoms to form distorted NHf5 trigonal bipyramids that share corners with two equivalent N(1)Hf4 tetrahedra, corners with five equivalent N(2)Hf4 tetrahedra, edges with two equivalent O(2)Hf6 octahedra,  an edgeedge with one N(2)Hf4 tetrahedra, edges with two equivalent N(1)Hf4 tetrahedra, and edges with two equivalent N(3)Hf5 trigonal bipyramids. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Hf(3) and three equivalent Hf(2) atoms. In the second O site, O(2) is bonded to two equivalent Hf(3) and four equivalent Hf(1) atoms to form OHf6 octahedra that share corners with two equivalent N(2)Hf4 tetrahedra, corners with four equivalent N(1)Hf4 tetrahedra, edges with two equivalent O(2)Hf6 octahedra, edges with two equivalent N(1)Hf4 tetrahedra, edges with four equivalent N(2)Hf4 tetrahedra, and edges with four equivalent N(3)Hf5 trigonal bipyramids. is represented by the CIF file [CIF]
data_Hf2N2O
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.042
_cell_length_b   7.042
_cell_length_c   8.177
_cell_angle_alpha   79.831
_cell_angle_beta   79.831
_cell_angle_gamma   26.744
_symmetry_Int_Tables_number   1
_cell_volume   179.443
_cell_formula_units_Z   3
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Hf  Hf0  1  0.970  0.970  0.809  1.0
  Hf  Hf1  1  0.371  0.371  0.475  1.0
  Hf  Hf2  1  0.304  0.304  0.132  1.0
  Hf  Hf3  1  0.696  0.696  0.868  1.0
  Hf  Hf4  1  0.629  0.629  0.525  1.0
  Hf  Hf5  1  0.030  0.030  0.191  1.0
  N  N6  1  0.465  0.465  0.657  1.0
  N  N7  1  0.828  0.828  0.964  1.0
  N  N8  1  0.873  0.873  0.285  1.0
  N  N9  1  0.127  0.127  0.715  1.0
  N  N10  1  0.172  0.172  0.036  1.0
  N  N11  1  0.535  0.535  0.343  1.0
  O  O12  1  0.790  0.790  0.617  1.0
  O  O13  1  0.210  0.210  0.383  1.0
  O  O14  1  0.500  0.500  0.000  1.0
[/CIF]
.