The material structure described by Hf2P2O9 crystallizes in the monoclinic C2/m space group. There are two inequivalent Hf sites. In the first Hf site, Hf(1) is bonded to one O(2), one O(3), one O(6), two equivalent O(1), and two equivalent O(4) atoms to form HfO7 pentagonal bipyramids that share  a cornercorner with one Hf(2)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  an edgeedge with one Hf(2)O6 octahedra,  an edgeedge with one Hf(1)O7 pentagonal bipyramid, and  an edgeedge with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 36°. In the second Hf site, Hf(2) is bonded to one O(3), one O(7), two equivalent O(5), and two equivalent O(6) atoms to form HfO6 octahedra that share  a cornercorner with one Hf(1)O7 pentagonal bipyramid,  a cornercorner with one P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra,  an edgeedge with one Hf(2)O6 octahedra, and  an edgeedge with one Hf(1)O7 pentagonal bipyramid. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(3), and two equivalent O(5) atoms to form PO4 tetrahedra that share corners with three equivalent Hf(2)O6 octahedra,  a cornercorner with one Hf(1)O7 pentagonal bipyramid, and  an edgeedge with one Hf(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 23-29°. In the second P site, P(2) is bonded to one O(2), one O(7), and two equivalent O(4) atoms to form PO4 tetrahedra that share  a cornercorner with one Hf(2)O6 octahedra and corners with three equivalent Hf(1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 39°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Hf(1) and one P(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Hf(1) and one P(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Hf(1), one Hf(2), and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Hf(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Hf(2) and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Hf(1) and two equivalent Hf(2) atoms. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Hf(2) and one P(2) atom. is represented by the CIF card [CIF]
data_Hf2P2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.559
_cell_length_b   7.559
_cell_length_c   10.010
_cell_angle_alpha   53.208
_cell_angle_beta   53.208
_cell_angle_gamma   51.488
_symmetry_Int_Tables_number   1
_cell_volume   334.235
_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  0.316  0.316  0.635  1.0
  Hf  Hf1  1  0.684  0.684  0.365  1.0
  Hf  Hf2  1  0.057  0.057  0.097  1.0
  Hf  Hf3  1  0.943  0.943  0.903  1.0
  P  P4  1  0.408  0.408  0.837  1.0
  P  P5  1  0.830  0.830  0.543  1.0
  P  P6  1  0.592  0.592  0.163  1.0
  P  P7  1  0.170  0.170  0.457  1.0
  O  O8  1  0.485  0.485  0.633  1.0
  O  O9  1  0.726  0.726  0.525  1.0
  O  O10  1  0.267  0.267  0.905  1.0
  O  O11  1  0.274  0.274  0.475  1.0
  O  O12  1  0.995  0.375  0.357  1.0
  O  O13  1  0.380  0.759  0.103  1.0
  O  O14  1  0.241  0.620  0.897  1.0
  O  O15  1  0.885  0.885  0.157  1.0
  O  O16  1  0.005  0.625  0.643  1.0
  O  O17  1  0.968  0.968  0.356  1.0
  O  O18  1  0.515  0.515  0.367  1.0
  O  O19  1  0.733  0.733  0.095  1.0
  O  O20  1  0.759  0.380  0.103  1.0
  O  O21  1  0.032  0.032  0.644  1.0
  O  O22  1  0.620  0.241  0.897  1.0
  O  O23  1  0.625  0.005  0.643  1.0
  O  O24  1  0.115  0.115  0.843  1.0
  O  O25  1  0.375  0.995  0.357  1.0
[/CIF]
.
The material structure described by Hf2P2O9 crystallizes in the monoclinic C2/m space group. There are two inequivalent Hf sites. In the first Hf site, Hf(1) is bonded to one O(2), one O(3), one O(6), two equivalent O(1), and two equivalent O(4) atoms to form HfO7 pentagonal bipyramids that share  a cornercorner with one Hf(2)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  an edgeedge with one Hf(2)O6 octahedra,  an edgeedge with one Hf(1)O7 pentagonal bipyramid, and  an edgeedge with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 36°. In the second Hf site, Hf(2) is bonded to one O(3), one O(7), two equivalent O(5), and two equivalent O(6) atoms to form HfO6 octahedra that share  a cornercorner with one Hf(1)O7 pentagonal bipyramid,  a cornercorner with one P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra,  an edgeedge with one Hf(2)O6 octahedra, and  an edgeedge with one Hf(1)O7 pentagonal bipyramid. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(3), and two equivalent O(5) atoms to form PO4 tetrahedra that share corners with three equivalent Hf(2)O6 octahedra,  a cornercorner with one Hf(1)O7 pentagonal bipyramid, and  an edgeedge with one Hf(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 23-29°. In the second P site, P(2) is bonded to one O(2), one O(7), and two equivalent O(4) atoms to form PO4 tetrahedra that share  a cornercorner with one Hf(2)O6 octahedra and corners with three equivalent Hf(1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 39°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Hf(1) and one P(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Hf(1) and one P(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Hf(1), one Hf(2), and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Hf(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Hf(2) and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Hf(1) and two equivalent Hf(2) atoms. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Hf(2) and one P(2) atom. is represented by the CIF card [CIF]
data_Hf2P2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.559
_cell_length_b   7.559
_cell_length_c   10.010
_cell_angle_alpha   53.208
_cell_angle_beta   53.208
_cell_angle_gamma   51.488
_symmetry_Int_Tables_number   1
_cell_volume   334.235
_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  0.316  0.316  0.635  1.0
  Hf  Hf1  1  0.684  0.684  0.365  1.0
  Hf  Hf2  1  0.057  0.057  0.097  1.0
  Hf  Hf3  1  0.943  0.943  0.903  1.0
  P  P4  1  0.408  0.408  0.837  1.0
  P  P5  1  0.830  0.830  0.543  1.0
  P  P6  1  0.592  0.592  0.163  1.0
  P  P7  1  0.170  0.170  0.457  1.0
  O  O8  1  0.485  0.485  0.633  1.0
  O  O9  1  0.726  0.726  0.525  1.0
  O  O10  1  0.267  0.267  0.905  1.0
  O  O11  1  0.274  0.274  0.475  1.0
  O  O12  1  0.995  0.375  0.357  1.0
  O  O13  1  0.380  0.759  0.103  1.0
  O  O14  1  0.241  0.620  0.897  1.0
  O  O15  1  0.885  0.885  0.157  1.0
  O  O16  1  0.005  0.625  0.643  1.0
  O  O17  1  0.968  0.968  0.356  1.0
  O  O18  1  0.515  0.515  0.367  1.0
  O  O19  1  0.733  0.733  0.095  1.0
  O  O20  1  0.759  0.380  0.103  1.0
  O  O21  1  0.032  0.032  0.644  1.0
  O  O22  1  0.620  0.241  0.897  1.0
  O  O23  1  0.625  0.005  0.643  1.0
  O  O24  1  0.115  0.115  0.843  1.0
  O  O25  1  0.375  0.995  0.357  1.0
[/CIF]
.