The crystal structure described by Na2Ni3O7 crystallizes in the triclinic P1 space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), one O(10), one O(14), one O(5), one O(7), and one O(9) atom to form NaO6 octahedra that share  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra,  an edgeedge with one Ni(5)O6 octahedra, and  an edgeedge with one Ni(6)O6 octahedra. In the second Na site, Na(2) is bonded in a distorted hexagonal planar geometry to one O(1), one O(10), one O(2), one O(4), one O(5), and one O(8) atom. In the third Na site, Na(3) is bonded in a 6-coordinate geometry to one O(10), one O(11), one O(12), one O(14), one O(5), and one O(6) atom. In the fourth Na site, Na(4) is bonded in a 6-coordinate geometry to one O(1), one O(11), one O(13), one O(14), one O(2), and one O(7) atom. There are six inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(1), one O(11), one O(2), one O(3), one O(5), and one O(6) atom to form NiO6 octahedra that share  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra,  an edgeedge with one Ni(5)O6 octahedra, and  an edgeedge with one Ni(6)O6 octahedra. In the second Ni site, Ni(2) is bonded to one O(1), one O(13), one O(3), one O(4), one O(7), and one O(8) atom to form NiO6 octahedra that share  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra,  an edgeedge with one Ni(5)O6 octahedra, and  an edgeedge with one Ni(6)O6 octahedra. In the third Ni site, Ni(3) is bonded to one O(10), one O(13), one O(14), one O(2), one O(4), and one O(6) atom to form NiO6 octahedra that share  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra,  an edgeedge with one Ni(5)O6 octahedra, and  an edgeedge with one Ni(6)O6 octahedra. In the fourth Ni site, Ni(4) is bonded to one O(12), one O(4), one O(5), one O(6), one O(8), and one O(9) atom to form NiO6 octahedra that share  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra,  an edgeedge with one Ni(5)O6 octahedra, and  an edgeedge with one Ni(6)O6 octahedra. In the fifth Ni site, Ni(5) is bonded to one O(10), one O(11), one O(12), one O(2), one O(7), and one O(8) atom to form NiO6 octahedra that share  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra, and  an edgeedge with one Ni(6)O6 octahedra. In the sixth Ni site, Ni(6) is bonded to one O(11), one O(12), one O(13), one O(14), one O(3), and one O(9) atom to form NiO6 octahedra that share  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra, and  an edgeedge with one Ni(5)O6 octahedra. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(2), one Na(4), one Ni(1), and one Ni(2) atom to form distorted ONa3Ni2 square pyramids that share  a cornercorner with one O(2)Na2Ni3 square pyramid,  a cornercorner with one O(5)Na3Ni2 square pyramid, corners with two equivalent O(14)Na3Ni2 square pyramids,  a cornercorner with one O(6)NaNi3 trigonal pyramid, corners with two equivalent O(4)NaNi3 trigonal pyramids,  an edgeedge with one O(11)Na2Ni3 square pyramid,  an edgeedge with one O(2)Na2Ni3 square pyramid,  an edgeedge with one O(10)Na3Ni2 square pyramid,  an edgeedge with one O(5)Na3Ni2 square pyramid, and  an edgeedge with one O(13)NaNi3 trigonal pyramid. In the second O site, O(2) is bonded to one Na(2), one Na(4), one Ni(1), one Ni(3), and one Ni(5) atom to form distorted ONa2Ni3 square pyramids that share  a cornercorner with one O(11)Na2Ni3 square pyramid,  a cornercorner with one O(1)Na3Ni2 square pyramid,  a cornercorner with one O(10)Na3Ni2 square pyramid,  a cornercorner with one O(12)NaNi3 trigonal pyramid, corners with two equivalent O(13)NaNi3 trigonal pyramids,  an edgeedge with one O(11)Na2Ni3 square pyramid,  an edgeedge with one O(1)Na3Ni2 square pyramid,  an edgeedge with one O(10)Na3Ni2 square pyramid,  an edgeedge with one O(14)Na3Ni2 square pyramid,  an edgeedge with one O(5)Na3Ni2 square pyramid,  an edgeedge with one O(4)NaNi3 trigonal pyramid, and  an edgeedge with one O(6)NaNi3 trigonal pyramid. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Ni(1), one Ni(2), and one Ni(6) atom. In the fourth O site, O(4) is bonded to one Na(2), one Ni(2), one Ni(3), and one Ni(4) atom to form distorted ONaNi3 trigonal pyramids that share  a cornercorner with one O(14)Na3Ni2 square pyramid, corners with two equivalent O(1)Na3Ni2 square pyramids, corners with two equivalent O(10)Na3Ni2 square pyramids,  a cornercorner with one O(12)NaNi3 trigonal pyramid,  an edgeedge with one O(2)Na2Ni3 square pyramid,  an edgeedge with one O(5)Na3Ni2 square pyramid,  an edgeedge with one O(13)NaNi3 trigonal pyramid, and  an edgeedge with one O(6)NaNi3 trigonal pyramid. In the fifth O site, O(5) is bonded to one Na(1), one Na(2), one Na(3), one Ni(1), and one Ni(4) atom to form distorted ONa3Ni2 square pyramids that share  a cornercorner with one O(1)Na3Ni2 square pyramid,  a cornercorner with one O(10)Na3Ni2 square pyramid, corners with two equivalent O(11)Na2Ni3 square pyramids,  a cornercorner with one O(6)NaNi3 trigonal pyramid,  an edgeedge with one O(2)Na2Ni3 square pyramid,  an edgeedge with one O(1)Na3Ni2 square pyramid,  an edgeedge with one O(10)Na3Ni2 square pyramid,  an edgeedge with one O(14)Na3Ni2 square pyramid,  an edgeedge with one O(12)NaNi3 trigonal pyramid,  an edgeedge with one O(4)NaNi3 trigonal pyramid, and  an edgeedge with one O(6)NaNi3 trigonal pyramid. In the sixth O site, O(6) is bonded to one Na(3), one Ni(1), one Ni(3), and one Ni(4) atom to form distorted ONaNi3 trigonal pyramids that share  a cornercorner with one O(1)Na3Ni2 square pyramid,  a cornercorner with one O(5)Na3Ni2 square pyramid, corners with two equivalent O(14)Na3Ni2 square pyramids,  a cornercorner with one O(13)NaNi3 trigonal pyramid, corners with two equivalent O(12)NaNi3 trigonal pyramids,  an edgeedge with one O(11)Na2Ni3 square pyramid,  an edgeedge with one O(2)Na2Ni3 square pyramid,  an edgeedge with one O(10)Na3Ni2 square pyramid,  an edgeedge with one O(5)Na3Ni2 square pyramid, and  an edgeedge with one O(4)NaNi3 trigonal pyramid. In the seventh O site, O(7) is bonded in a rectangular see-saw-like geometry to one Na(1), one Na(4), one Ni(2), and one Ni(5) atom. In the eighth O site, O(8) is bonded in a distorted see-saw-like geometry to one Na(2), one Ni(2), one Ni(4), and one Ni(5) atom. In the ninth O site, O(9) is bonded in a distorted T-shaped geometry to one Na(1), one Ni(4), and one Ni(6) atom. In the tenth O site, O(10) is bonded to one Na(1), one Na(2), one Na(3), one Ni(3), and one Ni(5) atom to form distorted ONa3Ni2 square pyramids that share  a cornercorner with one O(2)Na2Ni3 square pyramid,  a cornercorner with one O(14)Na3Ni2 square pyramid,  a cornercorner with one O(5)Na3Ni2 square pyramid,  a cornercorner with one O(13)NaNi3 trigonal pyramid, corners with two equivalent O(12)NaNi3 trigonal pyramids, corners with two equivalent O(4)NaNi3 trigonal pyramids,  an edgeedge with one O(11)Na2Ni3 square pyramid,  an edgeedge with one O(2)Na2Ni3 square pyramid,  an edgeedge with one O(1)Na3Ni2 square pyramid,  an edgeedge with one O(14)Na3Ni2 square pyramid,  an edgeedge with one O(5)Na3Ni2 square pyramid, and  an edgeedge with one O(6)NaNi3 trigonal pyramid. In the eleventh O site, O(11) is bonded to one Na(3), one Na(4), one Ni(1), one Ni(5), and one Ni(6) atom to form distorted ONa2Ni3 square pyramids that share  a cornercorner with one O(2)Na2Ni3 square pyramid,  a cornercorner with one O(14)Na3Ni2 square pyramid, corners with two equivalent O(5)Na3Ni2 square pyramids,  a cornercorner with one O(12)NaNi3 trigonal pyramid,  an edgeedge with one O(2)Na2Ni3 square pyramid,  an edgeedge with one O(1)Na3Ni2 square pyramid,  an edgeedge with one O(10)Na3Ni2 square pyramid,  an edgeedge with one O(14)Na3Ni2 square pyramid,  an edgeedge with one O(12)NaNi3 trigonal pyramid,  an edgeedge with one O(13)NaNi3 trigonal pyramid, and  an edgeedge with one O(6)NaNi3 trigonal pyramid. In the twelfth O site, O(12) is bonded to one Na(3), one Ni(4), one Ni(5), and one Ni(6) atom to form ONaNi3 trigonal pyramids that share  a cornercorner with one O(11)Na2Ni3 square pyramid,  a cornercorner with one O(2)Na2Ni3 square pyramid, corners with two equivalent O(10)Na3Ni2 square pyramids,  a cornercorner with one O(13)NaNi3 trigonal pyramid,  a cornercorner with one O(4)NaNi3 trigonal pyramid, corners with two equivalent O(6)NaNi3 trigonal pyramids,  an edgeedge with one O(11)Na2Ni3 square pyramid,  an edgeedge with one O(14)Na3Ni2 square pyramid, and  an edgeedge with one O(5)Na3Ni2 square pyramid. In the thirteenth O site, O(13) is bonded to one Na(4), one Ni(2), one Ni(3), and one Ni(6) atom to form ONaNi3 trigonal pyramids that share  a cornercorner with one O(10)Na3Ni2 square pyramid,  a cornercorner with one O(14)Na3Ni2 square pyramid, corners with two equivalent O(2)Na2Ni3 square pyramids,  a cornercorner with one O(12)NaNi3 trigonal pyramid,  a cornercorner with one O(6)NaNi3 trigonal pyramid,  an edgeedge with one O(11)Na2Ni3 square pyramid,  an edgeedge with one O(1)Na3Ni2 square pyramid,  an edgeedge with one O(14)Na3Ni2 square pyramid, and  an edgeedge with one O(4)NaNi3 trigonal pyramid. In the fourteenth O site, O(14) is bonded to one Na(1), one Na(3), one Na(4), one Ni(3), and one Ni(6) atom to form distorted ONa3Ni2 square pyramids that share  a cornercorner with one O(11)Na2Ni3 square pyramid,  a cornercorner with one O(10)Na3Ni2 square pyramid, corners with two equivalent O(1)Na3Ni2 square pyramids,  a cornercorner with one O(13)NaNi3 trigonal pyramid,  a cornercorner with one O(4)NaNi3 trigonal pyramid, corners with two equivalent O(6)NaNi3 trigonal pyramids,  an edgeedge with one O(11)Na2Ni3 square pyramid,  an edgeedge with one O(2)Na2Ni3 square pyramid,  an edgeedge with one O(10)Na3Ni2 square pyramid,  an edgeedge with one O(5)Na3Ni2 square pyramid,  an edgeedge with one O(12)NaNi3 trigonal pyramid, and  an edgeedge with one O(13)NaNi3 trigonal pyramid. is represented by the CIF card [CIF]
data_Na2Ni3O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.053
_cell_length_b   7.089
_cell_length_c   7.091
_cell_angle_alpha   64.186
_cell_angle_beta   64.118
_cell_angle_gamma   64.401
_symmetry_Int_Tables_number   1
_cell_volume   274.058
_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
  Na  Na0  1  0.135  0.283  0.563  1.0
  Na  Na1  1  0.198  0.952  0.358  1.0
  Na  Na2  1  0.029  0.634  0.831  1.0
  Na  Na3  1  0.422  0.208  0.869  1.0
  Ni  Ni4  1  0.288  0.572  0.144  1.0
  Ni  Ni5  1  0.577  0.143  0.284  1.0
  Ni  Ni6  1  0.001  0.998  0.001  1.0
  Ni  Ni7  1  0.852  0.716  0.428  1.0
  Ni  Ni8  1  0.431  0.852  0.714  1.0
  Ni  Ni9  1  0.714  0.429  0.860  1.0
  O  O10  1  0.305  0.277  0.229  1.0
  O  O11  1  0.298  0.872  0.008  1.0
  O  O12  1  0.580  0.439  0.158  1.0
  O  O13  1  0.870  0.008  0.293  1.0
  O  O14  1  0.143  0.620  0.423  1.0
  O  O15  1  0.990  0.703  0.137  1.0
  O  O16  1  0.474  0.125  0.577  1.0
  O  O17  1  0.553  0.854  0.418  1.0
  O  O18  1  0.798  0.446  0.570  1.0
  O  O19  1  0.138  0.944  0.726  1.0
  O  O20  1  0.417  0.559  0.854  1.0
  O  O21  1  0.728  0.720  0.723  1.0
  O  O22  1  0.711  0.133  0.989  1.0
  O  O23  1  0.994  0.292  0.902  1.0
[/CIF]
.
The crystal structure described by Na2Ni3O7 crystallizes in the triclinic P1 space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), one O(10), one O(14), one O(5), one O(7), and one O(9) atom to form NaO6 octahedra that share  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra,  an edgeedge with one Ni(5)O6 octahedra, and  an edgeedge with one Ni(6)O6 octahedra. In the second Na site, Na(2) is bonded in a distorted hexagonal planar geometry to one O(1), one O(10), one O(2), one O(4), one O(5), and one O(8) atom. In the third Na site, Na(3) is bonded in a 6-coordinate geometry to one O(10), one O(11), one O(12), one O(14), one O(5), and one O(6) atom. In the fourth Na site, Na(4) is bonded in a 6-coordinate geometry to one O(1), one O(11), one O(13), one O(14), one O(2), and one O(7) atom. There are six inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(1), one O(11), one O(2), one O(3), one O(5), and one O(6) atom to form NiO6 octahedra that share  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra,  an edgeedge with one Ni(5)O6 octahedra, and  an edgeedge with one Ni(6)O6 octahedra. In the second Ni site, Ni(2) is bonded to one O(1), one O(13), one O(3), one O(4), one O(7), and one O(8) atom to form NiO6 octahedra that share  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra,  an edgeedge with one Ni(5)O6 octahedra, and  an edgeedge with one Ni(6)O6 octahedra. In the third Ni site, Ni(3) is bonded to one O(10), one O(13), one O(14), one O(2), one O(4), and one O(6) atom to form NiO6 octahedra that share  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra,  an edgeedge with one Ni(5)O6 octahedra, and  an edgeedge with one Ni(6)O6 octahedra. In the fourth Ni site, Ni(4) is bonded to one O(12), one O(4), one O(5), one O(6), one O(8), and one O(9) atom to form NiO6 octahedra that share  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra,  an edgeedge with one Ni(5)O6 octahedra, and  an edgeedge with one Ni(6)O6 octahedra. In the fifth Ni site, Ni(5) is bonded to one O(10), one O(11), one O(12), one O(2), one O(7), and one O(8) atom to form NiO6 octahedra that share  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra, and  an edgeedge with one Ni(6)O6 octahedra. In the sixth Ni site, Ni(6) is bonded to one O(11), one O(12), one O(13), one O(14), one O(3), and one O(9) atom to form NiO6 octahedra that share  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra, and  an edgeedge with one Ni(5)O6 octahedra. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(2), one Na(4), one Ni(1), and one Ni(2) atom to form distorted ONa3Ni2 square pyramids that share  a cornercorner with one O(2)Na2Ni3 square pyramid,  a cornercorner with one O(5)Na3Ni2 square pyramid, corners with two equivalent O(14)Na3Ni2 square pyramids,  a cornercorner with one O(6)NaNi3 trigonal pyramid, corners with two equivalent O(4)NaNi3 trigonal pyramids,  an edgeedge with one O(11)Na2Ni3 square pyramid,  an edgeedge with one O(2)Na2Ni3 square pyramid,  an edgeedge with one O(10)Na3Ni2 square pyramid,  an edgeedge with one O(5)Na3Ni2 square pyramid, and  an edgeedge with one O(13)NaNi3 trigonal pyramid. In the second O site, O(2) is bonded to one Na(2), one Na(4), one Ni(1), one Ni(3), and one Ni(5) atom to form distorted ONa2Ni3 square pyramids that share  a cornercorner with one O(11)Na2Ni3 square pyramid,  a cornercorner with one O(1)Na3Ni2 square pyramid,  a cornercorner with one O(10)Na3Ni2 square pyramid,  a cornercorner with one O(12)NaNi3 trigonal pyramid, corners with two equivalent O(13)NaNi3 trigonal pyramids,  an edgeedge with one O(11)Na2Ni3 square pyramid,  an edgeedge with one O(1)Na3Ni2 square pyramid,  an edgeedge with one O(10)Na3Ni2 square pyramid,  an edgeedge with one O(14)Na3Ni2 square pyramid,  an edgeedge with one O(5)Na3Ni2 square pyramid,  an edgeedge with one O(4)NaNi3 trigonal pyramid, and  an edgeedge with one O(6)NaNi3 trigonal pyramid. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Ni(1), one Ni(2), and one Ni(6) atom. In the fourth O site, O(4) is bonded to one Na(2), one Ni(2), one Ni(3), and one Ni(4) atom to form distorted ONaNi3 trigonal pyramids that share  a cornercorner with one O(14)Na3Ni2 square pyramid, corners with two equivalent O(1)Na3Ni2 square pyramids, corners with two equivalent O(10)Na3Ni2 square pyramids,  a cornercorner with one O(12)NaNi3 trigonal pyramid,  an edgeedge with one O(2)Na2Ni3 square pyramid,  an edgeedge with one O(5)Na3Ni2 square pyramid,  an edgeedge with one O(13)NaNi3 trigonal pyramid, and  an edgeedge with one O(6)NaNi3 trigonal pyramid. In the fifth O site, O(5) is bonded to one Na(1), one Na(2), one Na(3), one Ni(1), and one Ni(4) atom to form distorted ONa3Ni2 square pyramids that share  a cornercorner with one O(1)Na3Ni2 square pyramid,  a cornercorner with one O(10)Na3Ni2 square pyramid, corners with two equivalent O(11)Na2Ni3 square pyramids,  a cornercorner with one O(6)NaNi3 trigonal pyramid,  an edgeedge with one O(2)Na2Ni3 square pyramid,  an edgeedge with one O(1)Na3Ni2 square pyramid,  an edgeedge with one O(10)Na3Ni2 square pyramid,  an edgeedge with one O(14)Na3Ni2 square pyramid,  an edgeedge with one O(12)NaNi3 trigonal pyramid,  an edgeedge with one O(4)NaNi3 trigonal pyramid, and  an edgeedge with one O(6)NaNi3 trigonal pyramid. In the sixth O site, O(6) is bonded to one Na(3), one Ni(1), one Ni(3), and one Ni(4) atom to form distorted ONaNi3 trigonal pyramids that share  a cornercorner with one O(1)Na3Ni2 square pyramid,  a cornercorner with one O(5)Na3Ni2 square pyramid, corners with two equivalent O(14)Na3Ni2 square pyramids,  a cornercorner with one O(13)NaNi3 trigonal pyramid, corners with two equivalent O(12)NaNi3 trigonal pyramids,  an edgeedge with one O(11)Na2Ni3 square pyramid,  an edgeedge with one O(2)Na2Ni3 square pyramid,  an edgeedge with one O(10)Na3Ni2 square pyramid,  an edgeedge with one O(5)Na3Ni2 square pyramid, and  an edgeedge with one O(4)NaNi3 trigonal pyramid. In the seventh O site, O(7) is bonded in a rectangular see-saw-like geometry to one Na(1), one Na(4), one Ni(2), and one Ni(5) atom. In the eighth O site, O(8) is bonded in a distorted see-saw-like geometry to one Na(2), one Ni(2), one Ni(4), and one Ni(5) atom. In the ninth O site, O(9) is bonded in a distorted T-shaped geometry to one Na(1), one Ni(4), and one Ni(6) atom. In the tenth O site, O(10) is bonded to one Na(1), one Na(2), one Na(3), one Ni(3), and one Ni(5) atom to form distorted ONa3Ni2 square pyramids that share  a cornercorner with one O(2)Na2Ni3 square pyramid,  a cornercorner with one O(14)Na3Ni2 square pyramid,  a cornercorner with one O(5)Na3Ni2 square pyramid,  a cornercorner with one O(13)NaNi3 trigonal pyramid, corners with two equivalent O(12)NaNi3 trigonal pyramids, corners with two equivalent O(4)NaNi3 trigonal pyramids,  an edgeedge with one O(11)Na2Ni3 square pyramid,  an edgeedge with one O(2)Na2Ni3 square pyramid,  an edgeedge with one O(1)Na3Ni2 square pyramid,  an edgeedge with one O(14)Na3Ni2 square pyramid,  an edgeedge with one O(5)Na3Ni2 square pyramid, and  an edgeedge with one O(6)NaNi3 trigonal pyramid. In the eleventh O site, O(11) is bonded to one Na(3), one Na(4), one Ni(1), one Ni(5), and one Ni(6) atom to form distorted ONa2Ni3 square pyramids that share  a cornercorner with one O(2)Na2Ni3 square pyramid,  a cornercorner with one O(14)Na3Ni2 square pyramid, corners with two equivalent O(5)Na3Ni2 square pyramids,  a cornercorner with one O(12)NaNi3 trigonal pyramid,  an edgeedge with one O(2)Na2Ni3 square pyramid,  an edgeedge with one O(1)Na3Ni2 square pyramid,  an edgeedge with one O(10)Na3Ni2 square pyramid,  an edgeedge with one O(14)Na3Ni2 square pyramid,  an edgeedge with one O(12)NaNi3 trigonal pyramid,  an edgeedge with one O(13)NaNi3 trigonal pyramid, and  an edgeedge with one O(6)NaNi3 trigonal pyramid. In the twelfth O site, O(12) is bonded to one Na(3), one Ni(4), one Ni(5), and one Ni(6) atom to form ONaNi3 trigonal pyramids that share  a cornercorner with one O(11)Na2Ni3 square pyramid,  a cornercorner with one O(2)Na2Ni3 square pyramid, corners with two equivalent O(10)Na3Ni2 square pyramids,  a cornercorner with one O(13)NaNi3 trigonal pyramid,  a cornercorner with one O(4)NaNi3 trigonal pyramid, corners with two equivalent O(6)NaNi3 trigonal pyramids,  an edgeedge with one O(11)Na2Ni3 square pyramid,  an edgeedge with one O(14)Na3Ni2 square pyramid, and  an edgeedge with one O(5)Na3Ni2 square pyramid. In the thirteenth O site, O(13) is bonded to one Na(4), one Ni(2), one Ni(3), and one Ni(6) atom to form ONaNi3 trigonal pyramids that share  a cornercorner with one O(10)Na3Ni2 square pyramid,  a cornercorner with one O(14)Na3Ni2 square pyramid, corners with two equivalent O(2)Na2Ni3 square pyramids,  a cornercorner with one O(12)NaNi3 trigonal pyramid,  a cornercorner with one O(6)NaNi3 trigonal pyramid,  an edgeedge with one O(11)Na2Ni3 square pyramid,  an edgeedge with one O(1)Na3Ni2 square pyramid,  an edgeedge with one O(14)Na3Ni2 square pyramid, and  an edgeedge with one O(4)NaNi3 trigonal pyramid. In the fourteenth O site, O(14) is bonded to one Na(1), one Na(3), one Na(4), one Ni(3), and one Ni(6) atom to form distorted ONa3Ni2 square pyramids that share  a cornercorner with one O(11)Na2Ni3 square pyramid,  a cornercorner with one O(10)Na3Ni2 square pyramid, corners with two equivalent O(1)Na3Ni2 square pyramids,  a cornercorner with one O(13)NaNi3 trigonal pyramid,  a cornercorner with one O(4)NaNi3 trigonal pyramid, corners with two equivalent O(6)NaNi3 trigonal pyramids,  an edgeedge with one O(11)Na2Ni3 square pyramid,  an edgeedge with one O(2)Na2Ni3 square pyramid,  an edgeedge with one O(10)Na3Ni2 square pyramid,  an edgeedge with one O(5)Na3Ni2 square pyramid,  an edgeedge with one O(12)NaNi3 trigonal pyramid, and  an edgeedge with one O(13)NaNi3 trigonal pyramid. is represented by the CIF card [CIF]
data_Na2Ni3O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.053
_cell_length_b   7.089
_cell_length_c   7.091
_cell_angle_alpha   64.186
_cell_angle_beta   64.118
_cell_angle_gamma   64.401
_symmetry_Int_Tables_number   1
_cell_volume   274.058
_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
  Na  Na0  1  0.135  0.283  0.563  1.0
  Na  Na1  1  0.198  0.952  0.358  1.0
  Na  Na2  1  0.029  0.634  0.831  1.0
  Na  Na3  1  0.422  0.208  0.869  1.0
  Ni  Ni4  1  0.288  0.572  0.144  1.0
  Ni  Ni5  1  0.577  0.143  0.284  1.0
  Ni  Ni6  1  0.001  0.998  0.001  1.0
  Ni  Ni7  1  0.852  0.716  0.428  1.0
  Ni  Ni8  1  0.431  0.852  0.714  1.0
  Ni  Ni9  1  0.714  0.429  0.860  1.0
  O  O10  1  0.305  0.277  0.229  1.0
  O  O11  1  0.298  0.872  0.008  1.0
  O  O12  1  0.580  0.439  0.158  1.0
  O  O13  1  0.870  0.008  0.293  1.0
  O  O14  1  0.143  0.620  0.423  1.0
  O  O15  1  0.990  0.703  0.137  1.0
  O  O16  1  0.474  0.125  0.577  1.0
  O  O17  1  0.553  0.854  0.418  1.0
  O  O18  1  0.798  0.446  0.570  1.0
  O  O19  1  0.138  0.944  0.726  1.0
  O  O20  1  0.417  0.559  0.854  1.0
  O  O21  1  0.728  0.720  0.723  1.0
  O  O22  1  0.711  0.133  0.989  1.0
  O  O23  1  0.994  0.292  0.902  1.0
[/CIF]
.