data_HfF3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.11
_cell_length_b   4.11
_cell_length_c   4.11
_cell_angle_alpha   131.88
_cell_angle_beta   131.88
_cell_angle_gamma   70.42
_symmetry_Int_Tables_number   1
_chemical_formula_structural   HfF3
_chemical_formula_sum   'Hf1 F3'
_cell_volume   37.63
_cell_formula_units_Z   1
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  Hf3  1  0.0  0.0  0.36  1.0
  F  F0  1  0.0  0.0  0.0  1.0
  F  F1  1  0.67  0.0  0.68  1.0
  F  F2  1  0.0  0.67  0.68  1.0

data_HfF3
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.74
_cell_length_b   4.74
_cell_length_c   4.11
_cell_angle_alpha   90.0
_cell_angle_beta   125.21
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   HfF3
_chemical_formula_sum   'Hf2 F6'
_cell_volume   75.26
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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  2  0.14  0.5  0.64  1.0
  F  F1  4  0.16  0.16  1.0  1.0
  F  F2  2  0.0  0.0  0.0  1.0

Hf F F F
HfF3 crystallizes in the monoclinic Cm space group. Hf(1) is bonded in a distorted single-bond geometry to one F(1) and four equivalent F(2) atoms. The Hf(1)-F(1) bond length is 1.46 Å. There are two shorter (2.13 Å) and two longer (2.43 Å) Hf(1)-F(2) bond lengths. There are two inequivalent F sites. In the first F site, F(1) is bonded in a distorted single-bond geometry to one Hf(1) and two equivalent F(2) atoms. Both F(1)-F(2) bond lengths are 1.08 Å. In the second F site, F(2) is bonded in a 3-coordinate geometry to two equivalent Hf(1) and one F(1) atom.