The material structure described by Na5Ni9O16 crystallizes in the monoclinic P2/m space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form distorted NaO6 octahedra that share corners with two equivalent Ni(3)O6 octahedra, corners with two equivalent Ni(4)O6 octahedra, corners with two equivalent Ni(5)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with two equivalent Ni(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-16°. In the second Na site, Na(2) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form distorted NaO6 octahedra that share corners with two equivalent Ni(5)O6 octahedra, corners with four equivalent Ni(3)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Ni(5)O6 octahedra, edges with four equivalent Na(3)O6 octahedra, and edges with four equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles are 13°. In the third Na site, Na(3) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form NaO6 octahedra that share corners with two equivalent Ni(2)O6 octahedra, corners with four equivalent Ni(1)O6 octahedra,  an edgeedge with one Na(3)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with two equivalent Ni(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-14°. There are six inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share corners with four equivalent Na(3)O6 octahedra,  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with two equivalent Ni(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-12°. In the second Ni site, Ni(2) is bonded to two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms to form NiO6 octahedra that share corners with two equivalent Na(3)O6 octahedra,  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. The corner-sharing octahedral tilt angles are 14°. In the third Ni site, Ni(3) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form NiO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Na(2)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra,  an edgeedge with one Ni(5)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with two equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 13-16°. In the fourth Ni site, Ni(4) is bonded to two equivalent O(5) and four equivalent O(2) atoms to form NiO6 octahedra that share corners with four equivalent Na(1)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with four equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles are 14°. In the fifth Ni site, Ni(5) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form NiO6 octahedra that share corners with two equivalent Na(2)O6 octahedra, corners with four equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, edges with four equivalent Na(3)O6 octahedra, and edges with four equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-13°. In the sixth Ni site, Ni(6) is bonded in a 6-coordinate geometry to two equivalent O(5) and four equivalent O(2) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(2), one Na(3), one Ni(1), one Ni(3), and one Ni(5) atom to form ONa3Ni3 octahedra that share corners with four equivalent O(1)Na3Ni3 octahedra, corners with two equivalent O(2)NaNi4 square pyramids, edges with three equivalent O(1)Na3Ni3 octahedra, edges with four equivalent O(3)Na3Ni3 octahedra,  an edgeedge with one O(2)NaNi4 square pyramid, and edges with four equivalent O(4)Na2Ni3 square pyramids. The corner-sharing octahedral tilt angles range from 0-8°. In the second O site, O(2) is bonded to one Na(1), one Ni(2), one Ni(3), one Ni(4), and one Ni(6) atom to form ONaNi4 square pyramids that share corners with two equivalent O(1)Na3Ni3 octahedra, corners with two equivalent O(4)Na2Ni3 square pyramids, corners with three equivalent O(2)NaNi4 square pyramids,  an edgeedge with one O(1)Na3Ni3 octahedra, edges with two equivalent O(4)Na2Ni3 square pyramids, and edges with three equivalent O(2)NaNi4 square pyramids. The corner-sharing octahedral tilt angles are 3°. In the third O site, O(3) is bonded to one Na(2), two equivalent Na(3), one Ni(5), and two equivalent Ni(1) atoms to form ONa3Ni3 octahedra that share corners with two equivalent O(3)Na3Ni3 octahedra, corners with four equivalent O(4)Na2Ni3 square pyramids, edges with two equivalent O(3)Na3Ni3 octahedra, edges with eight equivalent O(1)Na3Ni3 octahedra, and edges with two equivalent O(4)Na2Ni3 square pyramids. The corner-sharing octahedra are not tilted. In the fourth O site, O(4) is bonded to one Na(1), one Na(3), one Ni(1), one Ni(2), and one Ni(3) atom to form ONa2Ni3 square pyramids that share corners with two equivalent O(3)Na3Ni3 octahedra, corners with two equivalent O(2)NaNi4 square pyramids, corners with three equivalent O(4)Na2Ni3 square pyramids,  an edgeedge with one O(3)Na3Ni3 octahedra, edges with four equivalent O(1)Na3Ni3 octahedra,  an edgeedge with one O(4)Na2Ni3 square pyramid, and edges with two equivalent O(2)NaNi4 square pyramids. The corner-sharing octahedral tilt angles range from 2-5°. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to one Ni(4), one Ni(6), and two equivalent Ni(2) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na5Ni9O16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.473
_cell_length_b   11.592
_cell_length_c   5.173
_cell_angle_alpha   90.000
_cell_angle_beta   70.942
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   310.238
_cell_formula_units_Z   1
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  0.500  0.119  0.000  1.0
  Na  Na1  1  0.500  0.375  0.000  1.0
  Na  Na2  1  0.500  0.631  0.000  1.0
  Na  Na3  1  0.500  0.239  0.500  1.0
  Na  Na4  1  0.500  0.511  0.500  1.0
  Ni  Ni5  1  0.000  0.249  0.000  1.0
  Ni  Ni6  1  0.000  0.754  0.000  1.0
  Ni  Ni7  1  0.000  0.501  0.000  1.0
  Ni  Ni8  1  0.000  0.996  0.000  1.0
  Ni  Ni9  1  0.000  0.627  0.500  1.0
  Ni  Ni10  1  0.000  0.875  0.500  1.0
  Ni  Ni11  1  0.000  0.123  0.500  1.0
  Ni  Ni12  1  0.000  0.375  0.500  1.0
  Ni  Ni13  1  0.500  0.875  0.000  1.0
  O  O14  1  0.199  0.496  0.268  1.0
  O  O15  1  0.199  0.254  0.268  1.0
  O  O16  1  0.199  0.761  0.241  1.0
  O  O17  1  0.199  0.989  0.241  1.0
  O  O18  1  0.199  0.375  0.780  1.0
  O  O19  1  0.191  0.121  0.791  1.0
  O  O20  1  0.208  0.875  0.799  1.0
  O  O21  1  0.191  0.629  0.791  1.0
  O  O22  1  0.801  0.375  0.220  1.0
  O  O23  1  0.809  0.121  0.209  1.0
  O  O24  1  0.792  0.875  0.201  1.0
  O  O25  1  0.809  0.629  0.209  1.0
  O  O26  1  0.801  0.761  0.759  1.0
  O  O27  1  0.801  0.989  0.759  1.0
  O  O28  1  0.801  0.496  0.732  1.0
  O  O29  1  0.801  0.254  0.732  1.0
[/CIF]
.
The material structure described by Na5Ni9O16 crystallizes in the monoclinic P2/m space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form distorted NaO6 octahedra that share corners with two equivalent Ni(3)O6 octahedra, corners with two equivalent Ni(4)O6 octahedra, corners with two equivalent Ni(5)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with two equivalent Ni(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-16°. In the second Na site, Na(2) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form distorted NaO6 octahedra that share corners with two equivalent Ni(5)O6 octahedra, corners with four equivalent Ni(3)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Ni(5)O6 octahedra, edges with four equivalent Na(3)O6 octahedra, and edges with four equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles are 13°. In the third Na site, Na(3) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form NaO6 octahedra that share corners with two equivalent Ni(2)O6 octahedra, corners with four equivalent Ni(1)O6 octahedra,  an edgeedge with one Na(3)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with two equivalent Ni(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-14°. There are six inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share corners with four equivalent Na(3)O6 octahedra,  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with two equivalent Ni(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-12°. In the second Ni site, Ni(2) is bonded to two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms to form NiO6 octahedra that share corners with two equivalent Na(3)O6 octahedra,  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. The corner-sharing octahedral tilt angles are 14°. In the third Ni site, Ni(3) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form NiO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Na(2)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra,  an edgeedge with one Ni(5)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with two equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 13-16°. In the fourth Ni site, Ni(4) is bonded to two equivalent O(5) and four equivalent O(2) atoms to form NiO6 octahedra that share corners with four equivalent Na(1)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with four equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles are 14°. In the fifth Ni site, Ni(5) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form NiO6 octahedra that share corners with two equivalent Na(2)O6 octahedra, corners with four equivalent Na(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, edges with four equivalent Na(3)O6 octahedra, and edges with four equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-13°. In the sixth Ni site, Ni(6) is bonded in a 6-coordinate geometry to two equivalent O(5) and four equivalent O(2) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(2), one Na(3), one Ni(1), one Ni(3), and one Ni(5) atom to form ONa3Ni3 octahedra that share corners with four equivalent O(1)Na3Ni3 octahedra, corners with two equivalent O(2)NaNi4 square pyramids, edges with three equivalent O(1)Na3Ni3 octahedra, edges with four equivalent O(3)Na3Ni3 octahedra,  an edgeedge with one O(2)NaNi4 square pyramid, and edges with four equivalent O(4)Na2Ni3 square pyramids. The corner-sharing octahedral tilt angles range from 0-8°. In the second O site, O(2) is bonded to one Na(1), one Ni(2), one Ni(3), one Ni(4), and one Ni(6) atom to form ONaNi4 square pyramids that share corners with two equivalent O(1)Na3Ni3 octahedra, corners with two equivalent O(4)Na2Ni3 square pyramids, corners with three equivalent O(2)NaNi4 square pyramids,  an edgeedge with one O(1)Na3Ni3 octahedra, edges with two equivalent O(4)Na2Ni3 square pyramids, and edges with three equivalent O(2)NaNi4 square pyramids. The corner-sharing octahedral tilt angles are 3°. In the third O site, O(3) is bonded to one Na(2), two equivalent Na(3), one Ni(5), and two equivalent Ni(1) atoms to form ONa3Ni3 octahedra that share corners with two equivalent O(3)Na3Ni3 octahedra, corners with four equivalent O(4)Na2Ni3 square pyramids, edges with two equivalent O(3)Na3Ni3 octahedra, edges with eight equivalent O(1)Na3Ni3 octahedra, and edges with two equivalent O(4)Na2Ni3 square pyramids. The corner-sharing octahedra are not tilted. In the fourth O site, O(4) is bonded to one Na(1), one Na(3), one Ni(1), one Ni(2), and one Ni(3) atom to form ONa2Ni3 square pyramids that share corners with two equivalent O(3)Na3Ni3 octahedra, corners with two equivalent O(2)NaNi4 square pyramids, corners with three equivalent O(4)Na2Ni3 square pyramids,  an edgeedge with one O(3)Na3Ni3 octahedra, edges with four equivalent O(1)Na3Ni3 octahedra,  an edgeedge with one O(4)Na2Ni3 square pyramid, and edges with two equivalent O(2)NaNi4 square pyramids. The corner-sharing octahedral tilt angles range from 2-5°. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to one Ni(4), one Ni(6), and two equivalent Ni(2) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na5Ni9O16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.473
_cell_length_b   11.592
_cell_length_c   5.173
_cell_angle_alpha   90.000
_cell_angle_beta   70.942
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   310.238
_cell_formula_units_Z   1
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  0.500  0.119  0.000  1.0
  Na  Na1  1  0.500  0.375  0.000  1.0
  Na  Na2  1  0.500  0.631  0.000  1.0
  Na  Na3  1  0.500  0.239  0.500  1.0
  Na  Na4  1  0.500  0.511  0.500  1.0
  Ni  Ni5  1  0.000  0.249  0.000  1.0
  Ni  Ni6  1  0.000  0.754  0.000  1.0
  Ni  Ni7  1  0.000  0.501  0.000  1.0
  Ni  Ni8  1  0.000  0.996  0.000  1.0
  Ni  Ni9  1  0.000  0.627  0.500  1.0
  Ni  Ni10  1  0.000  0.875  0.500  1.0
  Ni  Ni11  1  0.000  0.123  0.500  1.0
  Ni  Ni12  1  0.000  0.375  0.500  1.0
  Ni  Ni13  1  0.500  0.875  0.000  1.0
  O  O14  1  0.199  0.496  0.268  1.0
  O  O15  1  0.199  0.254  0.268  1.0
  O  O16  1  0.199  0.761  0.241  1.0
  O  O17  1  0.199  0.989  0.241  1.0
  O  O18  1  0.199  0.375  0.780  1.0
  O  O19  1  0.191  0.121  0.791  1.0
  O  O20  1  0.208  0.875  0.799  1.0
  O  O21  1  0.191  0.629  0.791  1.0
  O  O22  1  0.801  0.375  0.220  1.0
  O  O23  1  0.809  0.121  0.209  1.0
  O  O24  1  0.792  0.875  0.201  1.0
  O  O25  1  0.809  0.629  0.209  1.0
  O  O26  1  0.801  0.761  0.759  1.0
  O  O27  1  0.801  0.989  0.759  1.0
  O  O28  1  0.801  0.496  0.732  1.0
  O  O29  1  0.801  0.254  0.732  1.0
[/CIF]
.