The structure described by HfO2 is Baddeleyite-like structured and crystallizes in the orthorhombic Pbca space group. Hf(1) is bonded to three equivalent O(2) and four equivalent O(1) atoms to form a mixture of distorted corner and edge-sharing HfO7 pentagonal bipyramids. There are two inequivalent O sites. In the first O site, O(1) 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(2) is bonded in a trigonal planar geometry to three equivalent Hf(1) atoms. is represented by the CIF file [CIF]
data_HfO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.038
_cell_length_b   5.202
_cell_length_c   9.972
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   261.354
_cell_formula_units_Z   8
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  0.754  0.465  0.885  1.0
  Hf  Hf1  1  0.254  0.535  0.615  1.0
  Hf  Hf2  1  0.746  0.965  0.115  1.0
  Hf  Hf3  1  0.246  0.035  0.385  1.0
  Hf  Hf4  1  0.246  0.535  0.115  1.0
  Hf  Hf5  1  0.746  0.465  0.385  1.0
  Hf  Hf6  1  0.254  0.035  0.885  1.0
  Hf  Hf7  1  0.754  0.965  0.615  1.0
  O  O8  1  0.998  0.261  0.523  1.0
  O  O9  1  0.498  0.739  0.977  1.0
  O  O10  1  0.502  0.761  0.477  1.0
  O  O11  1  0.002  0.239  0.023  1.0
  O  O12  1  0.002  0.739  0.477  1.0
  O  O13  1  0.502  0.261  0.023  1.0
  O  O14  1  0.498  0.239  0.523  1.0
  O  O15  1  0.998  0.761  0.977  1.0
  O  O16  1  0.626  0.626  0.711  1.0
  O  O17  1  0.126  0.374  0.789  1.0
  O  O18  1  0.874  0.126  0.289  1.0
  O  O19  1  0.374  0.874  0.211  1.0
  O  O20  1  0.374  0.374  0.289  1.0
  O  O21  1  0.874  0.626  0.211  1.0
  O  O22  1  0.126  0.874  0.711  1.0
  O  O23  1  0.626  0.126  0.789  1.0
[/CIF]
.
The structure described by HfO2 is Baddeleyite-like structured and crystallizes in the orthorhombic Pbca space group. Hf(1) is bonded to three equivalent O(2) and four equivalent O(1) atoms to form a mixture of distorted corner and edge-sharing HfO7 pentagonal bipyramids. There are two inequivalent O sites. In the first O site, O(1) 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(2) is bonded in a trigonal planar geometry to three equivalent Hf(1) atoms. is represented by the CIF file [CIF]
data_HfO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.038
_cell_length_b   5.202
_cell_length_c   9.972
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   261.354
_cell_formula_units_Z   8
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  0.754  0.465  0.885  1.0
  Hf  Hf1  1  0.254  0.535  0.615  1.0
  Hf  Hf2  1  0.746  0.965  0.115  1.0
  Hf  Hf3  1  0.246  0.035  0.385  1.0
  Hf  Hf4  1  0.246  0.535  0.115  1.0
  Hf  Hf5  1  0.746  0.465  0.385  1.0
  Hf  Hf6  1  0.254  0.035  0.885  1.0
  Hf  Hf7  1  0.754  0.965  0.615  1.0
  O  O8  1  0.998  0.261  0.523  1.0
  O  O9  1  0.498  0.739  0.977  1.0
  O  O10  1  0.502  0.761  0.477  1.0
  O  O11  1  0.002  0.239  0.023  1.0
  O  O12  1  0.002  0.739  0.477  1.0
  O  O13  1  0.502  0.261  0.023  1.0
  O  O14  1  0.498  0.239  0.523  1.0
  O  O15  1  0.998  0.761  0.977  1.0
  O  O16  1  0.626  0.626  0.711  1.0
  O  O17  1  0.126  0.374  0.789  1.0
  O  O18  1  0.874  0.126  0.289  1.0
  O  O19  1  0.374  0.874  0.211  1.0
  O  O20  1  0.374  0.374  0.289  1.0
  O  O21  1  0.874  0.626  0.211  1.0
  O  O22  1  0.126  0.874  0.711  1.0
  O  O23  1  0.626  0.126  0.789  1.0
[/CIF]
.