The compound described by Na2NiCPO7 crystallizes in the monoclinic Pc space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom. In the second Na site, Na(2) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom. In the third Na site, Na(3) is bonded to one O(10), one O(11), one O(12), one O(13), one O(14), one O(8), and one O(9) atom to form distorted NaO7 pentagonal bipyramids that share  a cornercorner with one Ni(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one P(2)O4 tetrahedra, and  a faceface with one Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles are 64°. In the fourth Na site, Na(4) is bonded in a 6-coordinate geometry to one O(10), one O(11), one O(2), one O(3), and two equivalent O(14) atoms. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(8) atom to form NiO6 octahedra that share  a cornercorner with one Na(3)O7 pentagonal bipyramid, corners with two equivalent P(1)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. In the second Ni site, Ni(2) is bonded to one O(10), one O(11), one O(12), one O(13), one O(7), and one O(9) atom to form NiO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  an edgeedge with one Na(3)O7 pentagonal bipyramid, and  a faceface with one Na(3)O7 pentagonal bipyramid. There are two inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one O(14), one O(2), and one O(3) atom. In the second C site, C(2) is bonded in a trigonal planar geometry to one O(1), one O(12), and one O(13) atom. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(4), one O(5), one O(7), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra, and  a cornercorner with one Na(3)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 37-50°. In the second P site, P(2) is bonded to one O(10), one O(11), one O(6), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra,  a cornercorner with one Na(3)O7 pentagonal bipyramid, and  an edgeedge with one Na(3)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 38-48°. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), and one C(2) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(4), one Ni(1), and one C(1) atom. In the third O site, O(3) is bonded in a 1-coordinate geometry to one Na(1), one Na(2), one Na(4), one Ni(1), and one C(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), one Ni(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Ni(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Ni(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Ni(2), and one P(1) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Na(3), one Ni(1), and one P(2) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Na(3), one Ni(2), and one P(1) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Na(3), one Na(4), one Ni(2), and one P(2) atom. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Na(3), one Na(4), one Ni(2), and one P(2) atom. In the twelfth O site, O(12) is bonded in a distorted T-shaped geometry to one Na(3), one Ni(2), and one C(2) atom. In the thirteenth O site, O(13) is bonded in a 3-coordinate geometry to one Na(3), one Ni(2), and one C(2) atom. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Na(3), two equivalent Na(4), and one C(1) atom. is represented by the CIF file [CIF]
data_Na2NiPCO7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.517
_cell_length_b   9.012
_cell_length_c   10.366
_cell_angle_alpha   88.547
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   608.603
_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
  Na  Na0  1  0.234  0.738  0.876  1.0
  Na  Na1  1  0.769  0.739  0.874  1.0
  Na  Na2  1  0.231  0.739  0.374  1.0
  Na  Na3  1  0.766  0.738  0.376  1.0
  Na  Na4  1  0.730  0.267  0.628  1.0
  Na  Na5  1  0.270  0.267  0.128  1.0
  Na  Na6  1  0.504  0.090  0.895  1.0
  Na  Na7  1  0.496  0.090  0.395  1.0
  Ni  Ni8  1  0.497  0.652  0.611  1.0
  Ni  Ni9  1  0.503  0.652  0.111  1.0
  Ni  Ni10  1  0.002  0.342  0.890  1.0
  Ni  Ni11  1  0.998  0.342  0.390  1.0
  P  P12  1  0.001  0.574  0.641  1.0
  P  P13  1  0.999  0.574  0.141  1.0
  P  P14  1  0.502  0.423  0.856  1.0
  P  P15  1  0.498  0.423  0.356  1.0
  C  C16  1  0.506  0.927  0.644  1.0
  C  C17  1  0.494  0.927  0.144  1.0
  C  C18  1  0.004  0.071  0.858  1.0
  C  C19  1  0.996  0.071  0.358  1.0
  O  O20  1  0.002  0.933  0.840  1.0
  O  O21  1  0.998  0.933  0.340  1.0
  O  O22  1  0.501  0.866  0.530  1.0
  O  O23  1  0.499  0.866  0.030  1.0
  O  O24  1  0.500  0.833  0.742  1.0
  O  O25  1  0.500  0.833  0.242  1.0
  O  O26  1  0.188  0.672  0.604  1.0
  O  O27  1  0.811  0.672  0.606  1.0
  O  O28  1  0.189  0.672  0.106  1.0
  O  O29  1  0.812  0.672  0.104  1.0
  O  O30  1  0.506  0.570  0.929  1.0
  O  O31  1  0.494  0.570  0.429  1.0
  O  O32  1  0.003  0.541  0.790  1.0
  O  O33  1  0.997  0.541  0.290  1.0
  O  O34  1  0.499  0.461  0.708  1.0
  O  O35  1  0.501  0.461  0.208  1.0
  O  O36  1  0.996  0.427  0.567  1.0
  O  O37  1  0.004  0.427  0.067  1.0
  O  O38  1  0.691  0.322  0.881  1.0
  O  O39  1  0.315  0.325  0.897  1.0
  O  O40  1  0.685  0.325  0.397  1.0
  O  O41  1  0.309  0.322  0.381  1.0
  O  O42  1  0.996  0.171  0.764  1.0
  O  O43  1  0.004  0.171  0.264  1.0
  O  O44  1  0.012  0.130  0.971  1.0
  O  O45  1  0.988  0.130  0.471  1.0
  O  O46  1  0.517  0.066  0.656  1.0
  O  O47  1  0.483  0.066  0.156  1.0
[/CIF]
.
The compound described by Na2NiCPO7 crystallizes in the monoclinic Pc space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom. In the second Na site, Na(2) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom. In the third Na site, Na(3) is bonded to one O(10), one O(11), one O(12), one O(13), one O(14), one O(8), and one O(9) atom to form distorted NaO7 pentagonal bipyramids that share  a cornercorner with one Ni(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one P(2)O4 tetrahedra, and  a faceface with one Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles are 64°. In the fourth Na site, Na(4) is bonded in a 6-coordinate geometry to one O(10), one O(11), one O(2), one O(3), and two equivalent O(14) atoms. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(8) atom to form NiO6 octahedra that share  a cornercorner with one Na(3)O7 pentagonal bipyramid, corners with two equivalent P(1)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. In the second Ni site, Ni(2) is bonded to one O(10), one O(11), one O(12), one O(13), one O(7), and one O(9) atom to form NiO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  an edgeedge with one Na(3)O7 pentagonal bipyramid, and  a faceface with one Na(3)O7 pentagonal bipyramid. There are two inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one O(14), one O(2), and one O(3) atom. In the second C site, C(2) is bonded in a trigonal planar geometry to one O(1), one O(12), and one O(13) atom. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(4), one O(5), one O(7), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra, and  a cornercorner with one Na(3)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 37-50°. In the second P site, P(2) is bonded to one O(10), one O(11), one O(6), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra,  a cornercorner with one Na(3)O7 pentagonal bipyramid, and  an edgeedge with one Na(3)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 38-48°. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), and one C(2) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(4), one Ni(1), and one C(1) atom. In the third O site, O(3) is bonded in a 1-coordinate geometry to one Na(1), one Na(2), one Na(4), one Ni(1), and one C(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), one Ni(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Ni(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Ni(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Ni(2), and one P(1) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Na(3), one Ni(1), and one P(2) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Na(3), one Ni(2), and one P(1) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Na(3), one Na(4), one Ni(2), and one P(2) atom. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Na(3), one Na(4), one Ni(2), and one P(2) atom. In the twelfth O site, O(12) is bonded in a distorted T-shaped geometry to one Na(3), one Ni(2), and one C(2) atom. In the thirteenth O site, O(13) is bonded in a 3-coordinate geometry to one Na(3), one Ni(2), and one C(2) atom. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Na(3), two equivalent Na(4), and one C(1) atom. is represented by the CIF file [CIF]
data_Na2NiPCO7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.517
_cell_length_b   9.012
_cell_length_c   10.366
_cell_angle_alpha   88.547
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   608.603
_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
  Na  Na0  1  0.234  0.738  0.876  1.0
  Na  Na1  1  0.769  0.739  0.874  1.0
  Na  Na2  1  0.231  0.739  0.374  1.0
  Na  Na3  1  0.766  0.738  0.376  1.0
  Na  Na4  1  0.730  0.267  0.628  1.0
  Na  Na5  1  0.270  0.267  0.128  1.0
  Na  Na6  1  0.504  0.090  0.895  1.0
  Na  Na7  1  0.496  0.090  0.395  1.0
  Ni  Ni8  1  0.497  0.652  0.611  1.0
  Ni  Ni9  1  0.503  0.652  0.111  1.0
  Ni  Ni10  1  0.002  0.342  0.890  1.0
  Ni  Ni11  1  0.998  0.342  0.390  1.0
  P  P12  1  0.001  0.574  0.641  1.0
  P  P13  1  0.999  0.574  0.141  1.0
  P  P14  1  0.502  0.423  0.856  1.0
  P  P15  1  0.498  0.423  0.356  1.0
  C  C16  1  0.506  0.927  0.644  1.0
  C  C17  1  0.494  0.927  0.144  1.0
  C  C18  1  0.004  0.071  0.858  1.0
  C  C19  1  0.996  0.071  0.358  1.0
  O  O20  1  0.002  0.933  0.840  1.0
  O  O21  1  0.998  0.933  0.340  1.0
  O  O22  1  0.501  0.866  0.530  1.0
  O  O23  1  0.499  0.866  0.030  1.0
  O  O24  1  0.500  0.833  0.742  1.0
  O  O25  1  0.500  0.833  0.242  1.0
  O  O26  1  0.188  0.672  0.604  1.0
  O  O27  1  0.811  0.672  0.606  1.0
  O  O28  1  0.189  0.672  0.106  1.0
  O  O29  1  0.812  0.672  0.104  1.0
  O  O30  1  0.506  0.570  0.929  1.0
  O  O31  1  0.494  0.570  0.429  1.0
  O  O32  1  0.003  0.541  0.790  1.0
  O  O33  1  0.997  0.541  0.290  1.0
  O  O34  1  0.499  0.461  0.708  1.0
  O  O35  1  0.501  0.461  0.208  1.0
  O  O36  1  0.996  0.427  0.567  1.0
  O  O37  1  0.004  0.427  0.067  1.0
  O  O38  1  0.691  0.322  0.881  1.0
  O  O39  1  0.315  0.325  0.897  1.0
  O  O40  1  0.685  0.325  0.397  1.0
  O  O41  1  0.309  0.322  0.381  1.0
  O  O42  1  0.996  0.171  0.764  1.0
  O  O43  1  0.004  0.171  0.264  1.0
  O  O44  1  0.012  0.130  0.971  1.0
  O  O45  1  0.988  0.130  0.471  1.0
  O  O46  1  0.517  0.066  0.656  1.0
  O  O47  1  0.483  0.066  0.156  1.0
[/CIF]
.