The material structure described by Ba2Ni(PO4)2 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one O(1), one O(3), one O(5), one O(7), one O(8), and two equivalent O(2) atoms to form distorted BaO7 pentagonal bipyramids that share corners with three equivalent Ni(1)O6 octahedra, corners with two equivalent Ba(1)O7 pentagonal bipyramids,  a cornercorner with one P(2)O4 tetrahedra, corners with four equivalent P(1)O4 tetrahedra,  an edgeedge with one Ni(1)O6 octahedra, and  an edgeedge with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 44-78°. In the second Ba site, Ba(2) is bonded in a 8-coordinate geometry to one O(2), one O(3), one O(5), one O(6), one O(7), one O(8), and two equivalent O(4) atoms. Ni(1) is bonded to one O(1), one O(3), one O(5), one O(6), one O(7), and one O(8) atom to form NiO6 octahedra that share corners with three equivalent Ba(1)O7 pentagonal bipyramids, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  an edgeedge with one Ba(1)O7 pentagonal bipyramid, and  an edgeedge with one P(2)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share corners with two equivalent Ni(1)O6 octahedra and corners with four equivalent Ba(1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 38-44°. In the second P site, P(2) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Ni(1)O6 octahedra,  a cornercorner with one Ba(1)O7 pentagonal bipyramid,  an edgeedge with one Ni(1)O6 octahedra, and  an edgeedge with one Ba(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 30-60°. There are eight inequivalent O sites. In the first O site, O(4) is bonded in a distorted single-bond geometry to two equivalent Ba(2) and one P(1) atom. In the second O site, O(5) is bonded in a 4-coordinate geometry to one Ba(1), one Ba(2), one Ni(1), and one P(2) atom. In the third O site, O(6) is bonded in a 2-coordinate geometry to one Ba(2), one Ni(1), and one P(2) atom. In the fourth O site, O(7) is bonded in a distorted single-bond geometry to one Ba(1), one Ba(2), one Ni(1), and one P(2) atom. In the fifth O site, O(8) is bonded in a 4-coordinate geometry to one Ba(1), one Ba(2), one Ni(1), and one P(2) atom. In the sixth O site, O(1) is bonded in a 3-coordinate geometry to one Ba(1), one Ni(1), and one P(1) atom. In the seventh O site, O(2) is bonded in a distorted single-bond geometry to one Ba(2), two equivalent Ba(1), and one P(1) atom. In the eighth O site, O(3) is bonded in a 3-coordinate geometry to one Ba(1), one Ba(2), one Ni(1), and one P(1) atom. is represented by the CIF file [CIF]
data_Ba2Ni(PO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.394
_cell_length_b   8.935
_cell_length_c   16.250
_cell_angle_alpha   90.000
_cell_angle_beta   90.815
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   783.102
_cell_formula_units_Z   4
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
  Ba  Ba0  1  0.243  0.654  0.770  1.0
  Ba  Ba1  1  0.257  0.154  0.730  1.0
  Ba  Ba2  1  0.757  0.346  0.230  1.0
  Ba  Ba3  1  0.743  0.846  0.270  1.0
  Ba  Ba4  1  0.802  0.203  0.481  1.0
  Ba  Ba5  1  0.698  0.703  0.019  1.0
  Ba  Ba6  1  0.198  0.797  0.519  1.0
  Ba  Ba7  1  0.302  0.297  0.981  1.0
  Ni  Ni8  1  0.775  0.012  0.867  1.0
  Ni  Ni9  1  0.725  0.512  0.633  1.0
  Ni  Ni10  1  0.275  0.488  0.367  1.0
  Ni  Ni11  1  0.225  0.988  0.133  1.0
  P  P12  1  0.748  0.888  0.667  1.0
  P  P13  1  0.752  0.388  0.833  1.0
  P  P14  1  0.252  0.112  0.333  1.0
  P  P15  1  0.248  0.612  0.167  1.0
  P  P16  1  0.232  0.914  0.922  1.0
  P  P17  1  0.732  0.586  0.422  1.0
  P  P18  1  0.768  0.086  0.078  1.0
  P  P19  1  0.268  0.414  0.578  1.0
  O  O20  1  0.852  0.970  0.745  1.0
  O  O21  1  0.648  0.470  0.755  1.0
  O  O22  1  0.148  0.030  0.255  1.0
  O  O23  1  0.352  0.530  0.245  1.0
  O  O24  1  0.460  0.887  0.666  1.0
  O  O25  1  0.040  0.387  0.834  1.0
  O  O26  1  0.540  0.113  0.334  1.0
  O  O27  1  0.960  0.613  0.166  1.0
  O  O28  1  0.856  0.724  0.668  1.0
  O  O29  1  0.644  0.224  0.832  1.0
  O  O30  1  0.144  0.276  0.332  1.0
  O  O31  1  0.356  0.776  0.168  1.0
  O  O32  1  0.847  0.970  0.589  1.0
  O  O33  1  0.653  0.470  0.911  1.0
  O  O34  1  0.153  0.030  0.411  1.0
  O  O35  1  0.347  0.530  0.089  1.0
  O  O36  1  0.468  0.866  0.873  1.0
  O  O37  1  0.032  0.366  0.627  1.0
  O  O38  1  0.532  0.134  0.127  1.0
  O  O39  1  0.968  0.634  0.373  1.0
  O  O40  1  0.791  0.588  0.514  1.0
  O  O41  1  0.709  0.088  0.986  1.0
  O  O42  1  0.209  0.412  0.486  1.0
  O  O43  1  0.291  0.912  0.014  1.0
  O  O44  1  0.515  0.695  0.400  1.0
  O  O45  1  0.985  0.195  0.100  1.0
  O  O46  1  0.146  0.070  0.889  1.0
  O  O47  1  0.015  0.805  0.900  1.0
  O  O48  1  0.646  0.430  0.389  1.0
  O  O49  1  0.854  0.930  0.111  1.0
  O  O50  1  0.354  0.570  0.611  1.0
  O  O51  1  0.485  0.305  0.600  1.0
[/CIF]
.
The material structure described by Ba2Ni(PO4)2 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one O(1), one O(3), one O(5), one O(7), one O(8), and two equivalent O(2) atoms to form distorted BaO7 pentagonal bipyramids that share corners with three equivalent Ni(1)O6 octahedra, corners with two equivalent Ba(1)O7 pentagonal bipyramids,  a cornercorner with one P(2)O4 tetrahedra, corners with four equivalent P(1)O4 tetrahedra,  an edgeedge with one Ni(1)O6 octahedra, and  an edgeedge with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 44-78°. In the second Ba site, Ba(2) is bonded in a 8-coordinate geometry to one O(2), one O(3), one O(5), one O(6), one O(7), one O(8), and two equivalent O(4) atoms. Ni(1) is bonded to one O(1), one O(3), one O(5), one O(6), one O(7), and one O(8) atom to form NiO6 octahedra that share corners with three equivalent Ba(1)O7 pentagonal bipyramids, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  an edgeedge with one Ba(1)O7 pentagonal bipyramid, and  an edgeedge with one P(2)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share corners with two equivalent Ni(1)O6 octahedra and corners with four equivalent Ba(1)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 38-44°. In the second P site, P(2) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Ni(1)O6 octahedra,  a cornercorner with one Ba(1)O7 pentagonal bipyramid,  an edgeedge with one Ni(1)O6 octahedra, and  an edgeedge with one Ba(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 30-60°. There are eight inequivalent O sites. In the first O site, O(4) is bonded in a distorted single-bond geometry to two equivalent Ba(2) and one P(1) atom. In the second O site, O(5) is bonded in a 4-coordinate geometry to one Ba(1), one Ba(2), one Ni(1), and one P(2) atom. In the third O site, O(6) is bonded in a 2-coordinate geometry to one Ba(2), one Ni(1), and one P(2) atom. In the fourth O site, O(7) is bonded in a distorted single-bond geometry to one Ba(1), one Ba(2), one Ni(1), and one P(2) atom. In the fifth O site, O(8) is bonded in a 4-coordinate geometry to one Ba(1), one Ba(2), one Ni(1), and one P(2) atom. In the sixth O site, O(1) is bonded in a 3-coordinate geometry to one Ba(1), one Ni(1), and one P(1) atom. In the seventh O site, O(2) is bonded in a distorted single-bond geometry to one Ba(2), two equivalent Ba(1), and one P(1) atom. In the eighth O site, O(3) is bonded in a 3-coordinate geometry to one Ba(1), one Ba(2), one Ni(1), and one P(1) atom. is represented by the CIF file [CIF]
data_Ba2Ni(PO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.394
_cell_length_b   8.935
_cell_length_c   16.250
_cell_angle_alpha   90.000
_cell_angle_beta   90.815
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   783.102
_cell_formula_units_Z   4
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
  Ba  Ba0  1  0.243  0.654  0.770  1.0
  Ba  Ba1  1  0.257  0.154  0.730  1.0
  Ba  Ba2  1  0.757  0.346  0.230  1.0
  Ba  Ba3  1  0.743  0.846  0.270  1.0
  Ba  Ba4  1  0.802  0.203  0.481  1.0
  Ba  Ba5  1  0.698  0.703  0.019  1.0
  Ba  Ba6  1  0.198  0.797  0.519  1.0
  Ba  Ba7  1  0.302  0.297  0.981  1.0
  Ni  Ni8  1  0.775  0.012  0.867  1.0
  Ni  Ni9  1  0.725  0.512  0.633  1.0
  Ni  Ni10  1  0.275  0.488  0.367  1.0
  Ni  Ni11  1  0.225  0.988  0.133  1.0
  P  P12  1  0.748  0.888  0.667  1.0
  P  P13  1  0.752  0.388  0.833  1.0
  P  P14  1  0.252  0.112  0.333  1.0
  P  P15  1  0.248  0.612  0.167  1.0
  P  P16  1  0.232  0.914  0.922  1.0
  P  P17  1  0.732  0.586  0.422  1.0
  P  P18  1  0.768  0.086  0.078  1.0
  P  P19  1  0.268  0.414  0.578  1.0
  O  O20  1  0.852  0.970  0.745  1.0
  O  O21  1  0.648  0.470  0.755  1.0
  O  O22  1  0.148  0.030  0.255  1.0
  O  O23  1  0.352  0.530  0.245  1.0
  O  O24  1  0.460  0.887  0.666  1.0
  O  O25  1  0.040  0.387  0.834  1.0
  O  O26  1  0.540  0.113  0.334  1.0
  O  O27  1  0.960  0.613  0.166  1.0
  O  O28  1  0.856  0.724  0.668  1.0
  O  O29  1  0.644  0.224  0.832  1.0
  O  O30  1  0.144  0.276  0.332  1.0
  O  O31  1  0.356  0.776  0.168  1.0
  O  O32  1  0.847  0.970  0.589  1.0
  O  O33  1  0.653  0.470  0.911  1.0
  O  O34  1  0.153  0.030  0.411  1.0
  O  O35  1  0.347  0.530  0.089  1.0
  O  O36  1  0.468  0.866  0.873  1.0
  O  O37  1  0.032  0.366  0.627  1.0
  O  O38  1  0.532  0.134  0.127  1.0
  O  O39  1  0.968  0.634  0.373  1.0
  O  O40  1  0.791  0.588  0.514  1.0
  O  O41  1  0.709  0.088  0.986  1.0
  O  O42  1  0.209  0.412  0.486  1.0
  O  O43  1  0.291  0.912  0.014  1.0
  O  O44  1  0.515  0.695  0.400  1.0
  O  O45  1  0.985  0.195  0.100  1.0
  O  O46  1  0.146  0.070  0.889  1.0
  O  O47  1  0.015  0.805  0.900  1.0
  O  O48  1  0.646  0.430  0.389  1.0
  O  O49  1  0.854  0.930  0.111  1.0
  O  O50  1  0.354  0.570  0.611  1.0
  O  O51  1  0.485  0.305  0.600  1.0
[/CIF]
.