data_HfP2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.72
_cell_length_b   4.72
_cell_length_c   5.11
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   HfP2
_chemical_formula_sum   'Hf2 P4'
_cell_volume   98.57
_cell_formula_units_Z   2
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  0.0  0.72  0.83  1.0
  Hf  Hf1  1  0.36  0.36  0.28  1.0
  P  P2  1  0.0  0.0  0.56  1.0
  P  P3  1  0.0  0.0  0.0  1.0
  P  P4  1  0.36  0.36  0.83  1.0
  P  P5  1  0.0  0.72  0.28  1.0

data_HfP2
_symmetry_space_group_name_H-M   P1
_cell_length_a   4.72
_cell_length_b   4.72
_cell_length_c   5.11
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   HfP2
_chemical_formula_sum   'Hf2 P4'
_cell_volume   98.57
_cell_formula_units_Z   2
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  0.0  0.72  0.83  1.0
  Hf  Hf1  1  0.36  0.36  0.28  1.0
  P  P2  1  0.0  0.0  0.0  1.0
  P  P3  1  0.0  0.0  0.56  1.0
  P  P4  1  0.0  0.72  0.28  1.0
  P  P5  1  0.36  0.36  0.83  1.0

Hf Hf P P P P
HfP2 crystallizes in the triclinic P1 space group. There are two inequivalent Hf sites. In the first Hf site, Hf(1) is bonded in a 2-coordinate geometry to one P(1), one P(2), two equivalent P(3), and two equivalent P(4) atoms. The Hf(1)-P(1) bond length is 1.93 Å. The Hf(1)-P(2) bond length is 1.55 Å. There is one shorter (2.63 Å) and one longer (2.95 Å) Hf(1)-P(3) bond length. There is one shorter (2.27 Å) and one longer (2.85 Å) Hf(1)-P(4) bond length. In the second Hf site, Hf(2) is bonded in a 7-coordinate geometry to one P(1), one P(2), two equivalent P(3), and three equivalent P(4) atoms. The Hf(2)-P(1) bond length is 2.22 Å. The Hf(2)-P(2) bond length is 2.22 Å. There is one shorter (2.27 Å) and one longer (2.85 Å) Hf(2)-P(3) bond length. There are a spread of Hf(2)-P(4) bond distances ranging from 2.61-2.95 Å. There are four inequivalent P sites. In the first P site, P(1) is bonded in a 2-coordinate geometry to one Hf(1), one Hf(2), one P(3), and one P(4) atom. The P(1)-P(3) bond length is 2.22 Å. The P(1)-P(4) bond length is 1.93 Å. In the second P site, P(2) is bonded in a distorted single-bond geometry to one Hf(1), one Hf(2), one P(3), and one P(4) atom. The P(2)-P(3) bond length is 1.90 Å. The P(2)-P(4) bond length is 1.93 Å. In the third P site, P(3) is bonded in a 6-coordinate geometry to two equivalent Hf(1), two equivalent Hf(2), one P(1), and one P(2) atom. In the fourth P site, P(4) is bonded to two equivalent Hf(1), three equivalent Hf(2), one P(1), and one P(2) atom to form distorted corner-sharing PHf5P2 pentagonal bipyramids.