The material structure described by Na3NiSiCO7 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms. In the second Na site, Na(2) is bonded to one O(1), one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms to form distorted NaO7 pentagonal bipyramids that share corners with two equivalent Na(2)O7 pentagonal bipyramids, corners with two equivalent Si(1)O4 tetrahedra,  an edgeedge with one Na(2)O7 pentagonal bipyramid,  an edgeedge with one Si(1)O4 tetrahedra, and  a faceface with one Na(2)O7 pentagonal bipyramid. Ni(1) is bonded in a 6-coordinate geometry to one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms. Si(1) is bonded to one O(5), one O(6), and two equivalent O(4) atoms to form SiO4 tetrahedra that share corners with four equivalent Na(2)O7 pentagonal bipyramids and edges with two equivalent Na(2)O7 pentagonal bipyramids. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. There are six inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Na(1), two equivalent Na(2), and one C(1) atom to form distorted corner-sharing ONa4C trigonal bipyramids. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(1), two equivalent Na(2), 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), two equivalent Na(2), one Ni(1), and one C(1) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Na(1), two equivalent Na(2), one Ni(1), and one Si(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Na(2), one Ni(1), and one Si(1) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na(2), one Ni(1), and one Si(1) atom. is represented by the CIF file [CIF]
data_Na3SiNiCO7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.461
_cell_length_b   5.223
_cell_length_c   9.077
_cell_angle_alpha   87.870
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   306.085
_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  0.750  0.231  0.913  1.0
  Na  Na1  1  0.988  0.748  0.728  1.0
  Na  Na2  1  0.512  0.748  0.728  1.0
  Na  Na3  1  0.488  0.252  0.272  1.0
  Na  Na4  1  0.012  0.252  0.272  1.0
  Na  Na5  1  0.250  0.769  0.087  1.0
  Si  Si6  1  0.750  0.294  0.570  1.0
  Si  Si7  1  0.250  0.706  0.430  1.0
  Ni  Ni8  1  0.250  0.216  0.655  1.0
  Ni  Ni9  1  0.750  0.784  0.345  1.0
  C  C10  1  0.250  0.283  0.938  1.0
  C  C11  1  0.750  0.717  0.062  1.0
  O  O12  1  0.750  0.734  0.920  1.0
  O  O13  1  0.250  0.071  0.865  1.0
  O  O14  1  0.250  0.498  0.866  1.0
  O  O15  1  0.946  0.231  0.684  1.0
  O  O16  1  0.554  0.231  0.684  1.0
  O  O17  1  0.750  0.609  0.534  1.0
  O  O18  1  0.250  0.860  0.580  1.0
  O  O19  1  0.750  0.140  0.420  1.0
  O  O20  1  0.250  0.391  0.466  1.0
  O  O21  1  0.446  0.769  0.316  1.0
  O  O22  1  0.054  0.769  0.316  1.0
  O  O23  1  0.750  0.502  0.134  1.0
  O  O24  1  0.750  0.929  0.135  1.0
  O  O25  1  0.250  0.266  0.080  1.0
[/CIF]
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The material structure described by Na3NiSiCO7 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms. In the second Na site, Na(2) is bonded to one O(1), one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms to form distorted NaO7 pentagonal bipyramids that share corners with two equivalent Na(2)O7 pentagonal bipyramids, corners with two equivalent Si(1)O4 tetrahedra,  an edgeedge with one Na(2)O7 pentagonal bipyramid,  an edgeedge with one Si(1)O4 tetrahedra, and  a faceface with one Na(2)O7 pentagonal bipyramid. Ni(1) is bonded in a 6-coordinate geometry to one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms. Si(1) is bonded to one O(5), one O(6), and two equivalent O(4) atoms to form SiO4 tetrahedra that share corners with four equivalent Na(2)O7 pentagonal bipyramids and edges with two equivalent Na(2)O7 pentagonal bipyramids. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. There are six inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Na(1), two equivalent Na(2), and one C(1) atom to form distorted corner-sharing ONa4C trigonal bipyramids. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(1), two equivalent Na(2), 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), two equivalent Na(2), one Ni(1), and one C(1) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Na(1), two equivalent Na(2), one Ni(1), and one Si(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Na(2), one Ni(1), and one Si(1) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na(2), one Ni(1), and one Si(1) atom. is represented by the CIF file [CIF]
data_Na3SiNiCO7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.461
_cell_length_b   5.223
_cell_length_c   9.077
_cell_angle_alpha   87.870
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   306.085
_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  0.750  0.231  0.913  1.0
  Na  Na1  1  0.988  0.748  0.728  1.0
  Na  Na2  1  0.512  0.748  0.728  1.0
  Na  Na3  1  0.488  0.252  0.272  1.0
  Na  Na4  1  0.012  0.252  0.272  1.0
  Na  Na5  1  0.250  0.769  0.087  1.0
  Si  Si6  1  0.750  0.294  0.570  1.0
  Si  Si7  1  0.250  0.706  0.430  1.0
  Ni  Ni8  1  0.250  0.216  0.655  1.0
  Ni  Ni9  1  0.750  0.784  0.345  1.0
  C  C10  1  0.250  0.283  0.938  1.0
  C  C11  1  0.750  0.717  0.062  1.0
  O  O12  1  0.750  0.734  0.920  1.0
  O  O13  1  0.250  0.071  0.865  1.0
  O  O14  1  0.250  0.498  0.866  1.0
  O  O15  1  0.946  0.231  0.684  1.0
  O  O16  1  0.554  0.231  0.684  1.0
  O  O17  1  0.750  0.609  0.534  1.0
  O  O18  1  0.250  0.860  0.580  1.0
  O  O19  1  0.750  0.140  0.420  1.0
  O  O20  1  0.250  0.391  0.466  1.0
  O  O21  1  0.446  0.769  0.316  1.0
  O  O22  1  0.054  0.769  0.316  1.0
  O  O23  1  0.750  0.502  0.134  1.0
  O  O24  1  0.750  0.929  0.135  1.0
  O  O25  1  0.250  0.266  0.080  1.0
[/CIF]
.