The material structure described by Ni4P2O9 crystallizes in the triclinic P-1 space group. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(1), one O(2), one O(3), one O(8), and one O(9) atom to form NiO5 trigonal bipyramids that share corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  a cornercorner with one Ni(2)O5 trigonal bipyramid, and  an edgeedge with one Ni(2)O5 trigonal bipyramid. In the second Ni site, Ni(2) is bonded to one O(1), one O(2), one O(4), one O(6), and one O(9) atom to form NiO5 trigonal bipyramids that share corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  a cornercorner with one Ni(1)O5 trigonal bipyramid, and  an edgeedge with one Ni(1)O5 trigonal bipyramid. In the third Ni site, Ni(3) is bonded in a rectangular see-saw-like geometry to one O(4), one O(7), one O(8), and one O(9) atom. In the fourth Ni site, Ni(4) is bonded in a 6-coordinate geometry to one O(3), one O(6), one O(7), one O(9), and two equivalent O(5) atoms. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(3), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Ni(1)O5 trigonal bipyramids and corners with two equivalent Ni(2)O5 trigonal bipyramids. In the second P site, P(2) is bonded to one O(1), one O(4), one O(5), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Ni(1)O5 trigonal bipyramids and corners with two equivalent Ni(2)O5 trigonal bipyramids. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Ni(1), one Ni(2), and one P(2) atom. In the second O site, O(2) is bonded in a trigonal non-coplanar geometry to one Ni(1), one Ni(2), and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ni(1), one Ni(4), and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Ni(2), one Ni(3), and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to two equivalent Ni(4) and one P(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Ni(2), one Ni(4), and one P(1) atom. In the seventh O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one Ni(3), one Ni(4), and one P(1) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Ni(1), one Ni(3), and one P(2) atom. In the ninth O site, O(9) is bonded in a tetrahedral geometry to one Ni(1), one Ni(2), one Ni(3), and one Ni(4) atom. is represented by the CIF card [CIF]
data_Ni4P2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.361
_cell_length_b   7.651
_cell_length_c   8.053
_cell_angle_alpha   98.137
_cell_angle_beta   112.314
_cell_angle_gamma   101.740
_symmetry_Int_Tables_number   1
_cell_volume   344.452
_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
  Ni  Ni0  1  0.078  0.881  0.733  1.0
  Ni  Ni1  1  0.603  0.889  0.737  1.0
  Ni  Ni2  1  0.638  0.670  0.437  1.0
  Ni  Ni3  1  0.830  0.601  0.906  1.0
  Ni  Ni4  1  0.170  0.399  0.094  1.0
  Ni  Ni5  1  0.362  0.330  0.563  1.0
  Ni  Ni6  1  0.397  0.111  0.263  1.0
  Ni  Ni7  1  0.922  0.119  0.267  1.0
  P  P8  1  0.482  0.780  0.075  1.0
  P  P9  1  0.119  0.741  0.354  1.0
  P  P10  1  0.881  0.259  0.646  1.0
  P  P11  1  0.518  0.220  0.925  1.0
  O  O12  1  0.144  0.936  0.315  1.0
  O  O13  1  0.611  0.958  0.238  1.0
  O  O14  1  0.231  0.788  0.958  1.0
  O  O15  1  0.366  0.723  0.479  1.0
  O  O16  1  0.009  0.590  0.173  1.0
  O  O17  1  0.631  0.776  0.962  1.0
  O  O18  1  0.473  0.614  0.167  1.0
  O  O19  1  0.969  0.719  0.467  1.0
  O  O20  1  0.777  0.717  0.699  1.0
  O  O21  1  0.223  0.283  0.301  1.0
  O  O22  1  0.031  0.281  0.533  1.0
  O  O23  1  0.527  0.386  0.833  1.0
  O  O24  1  0.369  0.224  0.038  1.0
  O  O25  1  0.991  0.410  0.827  1.0
  O  O26  1  0.634  0.277  0.521  1.0
  O  O27  1  0.769  0.212  0.042  1.0
  O  O28  1  0.389  0.042  0.762  1.0
  O  O29  1  0.856  0.064  0.685  1.0
[/CIF]
.
The material structure described by Ni4P2O9 crystallizes in the triclinic P-1 space group. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(1), one O(2), one O(3), one O(8), and one O(9) atom to form NiO5 trigonal bipyramids that share corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  a cornercorner with one Ni(2)O5 trigonal bipyramid, and  an edgeedge with one Ni(2)O5 trigonal bipyramid. In the second Ni site, Ni(2) is bonded to one O(1), one O(2), one O(4), one O(6), and one O(9) atom to form NiO5 trigonal bipyramids that share corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  a cornercorner with one Ni(1)O5 trigonal bipyramid, and  an edgeedge with one Ni(1)O5 trigonal bipyramid. In the third Ni site, Ni(3) is bonded in a rectangular see-saw-like geometry to one O(4), one O(7), one O(8), and one O(9) atom. In the fourth Ni site, Ni(4) is bonded in a 6-coordinate geometry to one O(3), one O(6), one O(7), one O(9), and two equivalent O(5) atoms. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(3), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Ni(1)O5 trigonal bipyramids and corners with two equivalent Ni(2)O5 trigonal bipyramids. In the second P site, P(2) is bonded to one O(1), one O(4), one O(5), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Ni(1)O5 trigonal bipyramids and corners with two equivalent Ni(2)O5 trigonal bipyramids. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Ni(1), one Ni(2), and one P(2) atom. In the second O site, O(2) is bonded in a trigonal non-coplanar geometry to one Ni(1), one Ni(2), and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ni(1), one Ni(4), and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Ni(2), one Ni(3), and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to two equivalent Ni(4) and one P(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Ni(2), one Ni(4), and one P(1) atom. In the seventh O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one Ni(3), one Ni(4), and one P(1) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Ni(1), one Ni(3), and one P(2) atom. In the ninth O site, O(9) is bonded in a tetrahedral geometry to one Ni(1), one Ni(2), one Ni(3), and one Ni(4) atom. is represented by the CIF card [CIF]
data_Ni4P2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.361
_cell_length_b   7.651
_cell_length_c   8.053
_cell_angle_alpha   98.137
_cell_angle_beta   112.314
_cell_angle_gamma   101.740
_symmetry_Int_Tables_number   1
_cell_volume   344.452
_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
  Ni  Ni0  1  0.078  0.881  0.733  1.0
  Ni  Ni1  1  0.603  0.889  0.737  1.0
  Ni  Ni2  1  0.638  0.670  0.437  1.0
  Ni  Ni3  1  0.830  0.601  0.906  1.0
  Ni  Ni4  1  0.170  0.399  0.094  1.0
  Ni  Ni5  1  0.362  0.330  0.563  1.0
  Ni  Ni6  1  0.397  0.111  0.263  1.0
  Ni  Ni7  1  0.922  0.119  0.267  1.0
  P  P8  1  0.482  0.780  0.075  1.0
  P  P9  1  0.119  0.741  0.354  1.0
  P  P10  1  0.881  0.259  0.646  1.0
  P  P11  1  0.518  0.220  0.925  1.0
  O  O12  1  0.144  0.936  0.315  1.0
  O  O13  1  0.611  0.958  0.238  1.0
  O  O14  1  0.231  0.788  0.958  1.0
  O  O15  1  0.366  0.723  0.479  1.0
  O  O16  1  0.009  0.590  0.173  1.0
  O  O17  1  0.631  0.776  0.962  1.0
  O  O18  1  0.473  0.614  0.167  1.0
  O  O19  1  0.969  0.719  0.467  1.0
  O  O20  1  0.777  0.717  0.699  1.0
  O  O21  1  0.223  0.283  0.301  1.0
  O  O22  1  0.031  0.281  0.533  1.0
  O  O23  1  0.527  0.386  0.833  1.0
  O  O24  1  0.369  0.224  0.038  1.0
  O  O25  1  0.991  0.410  0.827  1.0
  O  O26  1  0.634  0.277  0.521  1.0
  O  O27  1  0.769  0.212  0.042  1.0
  O  O28  1  0.389  0.042  0.762  1.0
  O  O29  1  0.856  0.064  0.685  1.0
[/CIF]
.