The material structure described by Na4Ni3O7 is Caswellsilverite-like structured and crystallizes in the trigonal R-3 space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(3), two equivalent O(1), and three equivalent O(2) atoms to form distorted NaO6 octahedra that share  a cornercorner with one Na(2)O6 octahedra, corners with five equivalent Ni(1)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra,  an edgeedge with one Na(3)O6 octahedra, edges with five equivalent Na(1)O6 octahedra, and edges with five equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-18°. In the second Na site, Na(2) is bonded to six equivalent O(2) atoms to form NaO6 octahedra that share corners with six equivalent Na(1)O6 octahedra, edges with six equivalent Na(1)O6 octahedra, and edges with six equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles are 18°. In the third Na site, Na(3) is bonded to six equivalent O(1) atoms to form distorted NaO6 octahedra that share corners with six equivalent Ni(1)O6 octahedra, edges with six equivalent Na(1)O6 octahedra, and edges with six equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles are 12°. Ni(1) is bonded to one O(3), two equivalent O(2), and three equivalent O(1) atoms to form NiO6 octahedra that share  a cornercorner with one Na(3)O6 octahedra, corners with five equivalent Na(1)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra,  an edgeedge with one Na(3)O6 octahedra, edges with five equivalent Na(1)O6 octahedra, and edges with five equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-16°. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Na(3), two equivalent Na(1), and three equivalent Ni(1) atoms to form ONa3Ni3 octahedra that share  a cornercorner with one O(3)Na3Ni3 octahedra, corners with two equivalent O(2)Na4Ni2 octahedra, corners with three equivalent O(1)Na3Ni3 octahedra, edges with two equivalent O(3)Na3Ni3 octahedra, edges with five equivalent O(1)Na3Ni3 octahedra, and edges with five equivalent O(2)Na4Ni2 octahedra. The corner-sharing octahedral tilt angles range from 0-11°. In the second O site, O(2) is bonded to one Na(2), three equivalent Na(1), and two equivalent Ni(1) atoms to form ONa4Ni2 octahedra that share  a cornercorner with one O(3)Na3Ni3 octahedra, corners with two equivalent O(1)Na3Ni3 octahedra, corners with three equivalent O(2)Na4Ni2 octahedra, edges with two equivalent O(3)Na3Ni3 octahedra, edges with five equivalent O(1)Na3Ni3 octahedra, and edges with five equivalent O(2)Na4Ni2 octahedra. The corner-sharing octahedral tilt angles range from 0-11°. In the third O site, O(3) is bonded to three equivalent Na(1) and three equivalent Ni(1) atoms to form distorted ONa3Ni3 octahedra that share corners with three equivalent O(1)Na3Ni3 octahedra, corners with three equivalent O(2)Na4Ni2 octahedra, edges with six equivalent O(1)Na3Ni3 octahedra, and edges with six equivalent O(2)Na4Ni2 octahedra. The corner-sharing octahedral tilt angles range from 5-7°. is represented by the CIF card [CIF]
data_Na4Ni3O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.006
_cell_length_b   7.006
_cell_length_c   7.006
_cell_angle_alpha   69.271
_cell_angle_beta   69.271
_cell_angle_gamma   69.271
_symmetry_Int_Tables_number   1
_cell_volume   290.366
_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  0.576  0.156  0.283  1.0
  Na  Na1  1  0.156  0.283  0.576  1.0
  Na  Na2  1  0.717  0.424  0.844  1.0
  Na  Na3  1  0.500  0.500  0.500  1.0
  Na  Na4  1  0.283  0.576  0.156  1.0
  Na  Na5  1  0.844  0.717  0.424  1.0
  Na  Na6  1  0.424  0.844  0.717  1.0
  Na  Na7  1  0.000  0.000  0.000  1.0
  Ni  Ni8  1  0.356  0.210  0.932  1.0
  Ni  Ni9  1  0.932  0.356  0.210  1.0
  Ni  Ni10  1  0.790  0.068  0.644  1.0
  Ni  Ni11  1  0.644  0.790  0.068  1.0
  Ni  Ni12  1  0.210  0.932  0.356  1.0
  Ni  Ni13  1  0.068  0.644  0.790  1.0
  O  O14  1  0.664  0.082  0.954  1.0
  O  O15  1  0.493  0.161  0.645  1.0
  O  O16  1  0.228  0.228  0.228  1.0
  O  O17  1  0.645  0.493  0.161  1.0
  O  O18  1  0.355  0.507  0.839  1.0
  O  O19  1  0.839  0.355  0.507  1.0
  O  O20  1  0.507  0.839  0.355  1.0
  O  O21  1  0.772  0.772  0.772  1.0
  O  O22  1  0.046  0.336  0.918  1.0
  O  O23  1  0.161  0.645  0.493  1.0
  O  O24  1  0.954  0.664  0.082  1.0
  O  O25  1  0.336  0.918  0.046  1.0
  O  O26  1  0.082  0.954  0.664  1.0
  O  O27  1  0.918  0.046  0.336  1.0
[/CIF]
.
The material structure described by Na4Ni3O7 is Caswellsilverite-like structured and crystallizes in the trigonal R-3 space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(3), two equivalent O(1), and three equivalent O(2) atoms to form distorted NaO6 octahedra that share  a cornercorner with one Na(2)O6 octahedra, corners with five equivalent Ni(1)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra,  an edgeedge with one Na(3)O6 octahedra, edges with five equivalent Na(1)O6 octahedra, and edges with five equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-18°. In the second Na site, Na(2) is bonded to six equivalent O(2) atoms to form NaO6 octahedra that share corners with six equivalent Na(1)O6 octahedra, edges with six equivalent Na(1)O6 octahedra, and edges with six equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles are 18°. In the third Na site, Na(3) is bonded to six equivalent O(1) atoms to form distorted NaO6 octahedra that share corners with six equivalent Ni(1)O6 octahedra, edges with six equivalent Na(1)O6 octahedra, and edges with six equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles are 12°. Ni(1) is bonded to one O(3), two equivalent O(2), and three equivalent O(1) atoms to form NiO6 octahedra that share  a cornercorner with one Na(3)O6 octahedra, corners with five equivalent Na(1)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra,  an edgeedge with one Na(3)O6 octahedra, edges with five equivalent Na(1)O6 octahedra, and edges with five equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-16°. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Na(3), two equivalent Na(1), and three equivalent Ni(1) atoms to form ONa3Ni3 octahedra that share  a cornercorner with one O(3)Na3Ni3 octahedra, corners with two equivalent O(2)Na4Ni2 octahedra, corners with three equivalent O(1)Na3Ni3 octahedra, edges with two equivalent O(3)Na3Ni3 octahedra, edges with five equivalent O(1)Na3Ni3 octahedra, and edges with five equivalent O(2)Na4Ni2 octahedra. The corner-sharing octahedral tilt angles range from 0-11°. In the second O site, O(2) is bonded to one Na(2), three equivalent Na(1), and two equivalent Ni(1) atoms to form ONa4Ni2 octahedra that share  a cornercorner with one O(3)Na3Ni3 octahedra, corners with two equivalent O(1)Na3Ni3 octahedra, corners with three equivalent O(2)Na4Ni2 octahedra, edges with two equivalent O(3)Na3Ni3 octahedra, edges with five equivalent O(1)Na3Ni3 octahedra, and edges with five equivalent O(2)Na4Ni2 octahedra. The corner-sharing octahedral tilt angles range from 0-11°. In the third O site, O(3) is bonded to three equivalent Na(1) and three equivalent Ni(1) atoms to form distorted ONa3Ni3 octahedra that share corners with three equivalent O(1)Na3Ni3 octahedra, corners with three equivalent O(2)Na4Ni2 octahedra, edges with six equivalent O(1)Na3Ni3 octahedra, and edges with six equivalent O(2)Na4Ni2 octahedra. The corner-sharing octahedral tilt angles range from 5-7°. is represented by the CIF card [CIF]
data_Na4Ni3O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.006
_cell_length_b   7.006
_cell_length_c   7.006
_cell_angle_alpha   69.271
_cell_angle_beta   69.271
_cell_angle_gamma   69.271
_symmetry_Int_Tables_number   1
_cell_volume   290.366
_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  0.576  0.156  0.283  1.0
  Na  Na1  1  0.156  0.283  0.576  1.0
  Na  Na2  1  0.717  0.424  0.844  1.0
  Na  Na3  1  0.500  0.500  0.500  1.0
  Na  Na4  1  0.283  0.576  0.156  1.0
  Na  Na5  1  0.844  0.717  0.424  1.0
  Na  Na6  1  0.424  0.844  0.717  1.0
  Na  Na7  1  0.000  0.000  0.000  1.0
  Ni  Ni8  1  0.356  0.210  0.932  1.0
  Ni  Ni9  1  0.932  0.356  0.210  1.0
  Ni  Ni10  1  0.790  0.068  0.644  1.0
  Ni  Ni11  1  0.644  0.790  0.068  1.0
  Ni  Ni12  1  0.210  0.932  0.356  1.0
  Ni  Ni13  1  0.068  0.644  0.790  1.0
  O  O14  1  0.664  0.082  0.954  1.0
  O  O15  1  0.493  0.161  0.645  1.0
  O  O16  1  0.228  0.228  0.228  1.0
  O  O17  1  0.645  0.493  0.161  1.0
  O  O18  1  0.355  0.507  0.839  1.0
  O  O19  1  0.839  0.355  0.507  1.0
  O  O20  1  0.507  0.839  0.355  1.0
  O  O21  1  0.772  0.772  0.772  1.0
  O  O22  1  0.046  0.336  0.918  1.0
  O  O23  1  0.161  0.645  0.493  1.0
  O  O24  1  0.954  0.664  0.082  1.0
  O  O25  1  0.336  0.918  0.046  1.0
  O  O26  1  0.082  0.954  0.664  1.0
  O  O27  1  0.918  0.046  0.336  1.0
[/CIF]
.