The crystal structure described by HfO2 is Cotunnite structured and crystallizes in the orthorhombic Pnma space group. Hf(1) is bonded in a 9-coordinate geometry to four equivalent O(2) and five equivalent O(1) atoms. There are two inequivalent O sites. In the first O site, O(2) is bonded to four equivalent Hf(1) atoms to form a mixture of corner and edge-sharing OHf4 tetrahedra. In the second O site, O(1) is bonded in a 5-coordinate geometry to five equivalent Hf(1) atoms. is represented by the CIF file [CIF]
data_HfO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.334
_cell_length_b   5.556
_cell_length_c   6.505
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   120.491
_cell_formula_units_Z   4
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  0.250  0.251  0.608  1.0
  Hf  Hf1  1  0.750  0.749  0.392  1.0
  Hf  Hf2  1  0.250  0.751  0.892  1.0
  Hf  Hf3  1  0.750  0.249  0.108  1.0
  O  O4  1  0.750  0.479  0.841  1.0
  O  O5  1  0.250  0.521  0.159  1.0
  O  O6  1  0.750  0.979  0.659  1.0
  O  O7  1  0.250  0.021  0.341  1.0
  O  O8  1  0.750  0.361  0.423  1.0
  O  O9  1  0.250  0.639  0.577  1.0
  O  O10  1  0.750  0.861  0.077  1.0
  O  O11  1  0.250  0.139  0.923  1.0
[/CIF]
.
The crystal structure described by HfO2 is Cotunnite structured and crystallizes in the orthorhombic Pnma space group. Hf(1) is bonded in a 9-coordinate geometry to four equivalent O(2) and five equivalent O(1) atoms. There are two inequivalent O sites. In the first O site, O(2) is bonded to four equivalent Hf(1) atoms to form a mixture of corner and edge-sharing OHf4 tetrahedra. In the second O site, O(1) is bonded in a 5-coordinate geometry to five equivalent Hf(1) atoms. is represented by the CIF file [CIF]
data_HfO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.334
_cell_length_b   5.556
_cell_length_c   6.505
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   120.491
_cell_formula_units_Z   4
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  0.250  0.251  0.608  1.0
  Hf  Hf1  1  0.750  0.749  0.392  1.0
  Hf  Hf2  1  0.250  0.751  0.892  1.0
  Hf  Hf3  1  0.750  0.249  0.108  1.0
  O  O4  1  0.750  0.479  0.841  1.0
  O  O5  1  0.250  0.521  0.159  1.0
  O  O6  1  0.750  0.979  0.659  1.0
  O  O7  1  0.250  0.021  0.341  1.0
  O  O8  1  0.750  0.361  0.423  1.0
  O  O9  1  0.250  0.639  0.577  1.0
  O  O10  1  0.750  0.861  0.077  1.0
  O  O11  1  0.250  0.139  0.923  1.0
[/CIF]
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