The structure described by Na2CoSiCO7 crystallizes in the triclinic P-1 space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), one O(4), one O(6), one O(8), one O(9), and two equivalent O(11) atoms to form distorted NaO7 pentagonal bipyramids that share corners with two equivalent Na(1)O7 pentagonal bipyramids,  a cornercorner with one Co(2)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Co(1)O5 trigonal bipyramid,  an edgeedge with one Si(1)O4 tetrahedra,  a faceface with one Na(4)O7 pentagonal bipyramid, and  a faceface with one Co(1)O5 trigonal bipyramid. In the second Na site, Na(2) is bonded to one O(10), one O(2), one O(3), one O(5), one O(7), and two equivalent O(12) atoms to form distorted NaO7 pentagonal bipyramids that share corners with two equivalent Na(2)O7 pentagonal bipyramids,  a cornercorner with one Co(2)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Co(1)O5 trigonal bipyramid,  an edgeedge with one Na(4)O7 pentagonal bipyramid,  an edgeedge with one Co(2)O4 tetrahedra, and  an edgeedge with one Si(2)O4 tetrahedra. In the third Na site, Na(3) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(5), one O(7), one O(9), and two equivalent O(13) atoms. In the fourth Na site, Na(4) is bonded to one O(10), one O(2), one O(4), one O(6), one O(8), and two equivalent O(14) atoms to form distorted NaO7 pentagonal bipyramids that share corners with two equivalent Na(4)O7 pentagonal bipyramids, corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Co(1)O5 trigonal bipyramids,  an edgeedge with one Na(2)O7 pentagonal bipyramid,  an edgeedge with one Si(2)O4 tetrahedra,  a faceface with one Na(1)O7 pentagonal bipyramid, and  a faceface with one Co(1)O5 trigonal bipyramid. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(10), one O(11), one O(14), one O(4), and one O(8) atom to form distorted CoO5 trigonal bipyramids that share  a cornercorner with one Na(1)O7 pentagonal bipyramid,  a cornercorner with one Na(2)O7 pentagonal bipyramid, corners with two equivalent Na(4)O7 pentagonal bipyramids,  a cornercorner with one Si(1)O4 tetrahedra, corners with three equivalent Si(2)O4 tetrahedra,  a faceface with one Na(1)O7 pentagonal bipyramid, and  a faceface with one Na(4)O7 pentagonal bipyramid. In the second Co site, Co(2) is bonded to one O(12), one O(13), one O(7), and one O(9) atom to form distorted CoO4 tetrahedra that share  a cornercorner with one Na(1)O7 pentagonal bipyramid,  a cornercorner with one Na(2)O7 pentagonal bipyramid,  a cornercorner with one Si(2)O4 tetrahedra, corners with three equivalent Si(1)O4 tetrahedra, and  an edgeedge with one Na(2)O7 pentagonal bipyramid. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(11), one O(13), one O(7), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Na(1)O7 pentagonal bipyramid,  a cornercorner with one Na(2)O7 pentagonal bipyramid, corners with three equivalent Co(2)O4 tetrahedra,  a cornercorner with one Co(1)O5 trigonal bipyramid, and  an edgeedge with one Na(1)O7 pentagonal bipyramid. In the second Si site, Si(2) is bonded to one O(10), one O(12), one O(14), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Na(1)O7 pentagonal bipyramid,  a cornercorner with one Na(2)O7 pentagonal bipyramid, corners with two equivalent Na(4)O7 pentagonal bipyramids,  a cornercorner with one Co(2)O4 tetrahedra, corners with three equivalent Co(1)O5 trigonal bipyramids,  an edgeedge with one Na(2)O7 pentagonal bipyramid, and  an edgeedge with one Na(4)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(1), one O(3), and one O(5) atom. In the second C site, C(2) is bonded in a trigonal planar geometry to one O(2), one O(4), and one O(6) atom. 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(3), and one C(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(2), one Na(4), and one C(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Na(2), one Na(3), and one C(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Na(1), one Na(4), one Co(1), and one C(2) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Na(2), one Na(3), and one C(1) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Na(1), one Na(4), and one C(2) atom. In the seventh O site, O(7) is bonded in a distorted rectangular see-saw-like geometry to one Na(2), one Na(3), one Co(2), and one Si(1) atom. In the eighth O site, O(8) is bonded in a rectangular see-saw-like geometry to one Na(1), one Na(4), one Co(1), and one Si(2) atom. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to one Na(1), one Na(3), one Co(2), and one Si(1) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Na(2), one Na(4), one Co(1), and one Si(2) atom. In the eleventh O site, O(11) is bonded in a 2-coordinate geometry to two equivalent Na(1), one Co(1), and one Si(1) atom. In the twelfth O site, O(12) is bonded in a 2-coordinate geometry to two equivalent Na(2), one Co(2), and one Si(2) atom. In the thirteenth O site, O(13) is bonded in a 2-coordinate geometry to two equivalent Na(3), one Co(2), and one Si(1) atom. In the fourteenth O site, O(14) is bonded in a 2-coordinate geometry to two equivalent Na(4), one Co(1), and one Si(2) atom. is represented by the CIF file [CIF]
data_Na2CoSiCO7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.151
_cell_length_b   9.670
_cell_length_c   12.584
_cell_angle_alpha   89.896
_cell_angle_beta   90.019
_cell_angle_gamma   90.842
_symmetry_Int_Tables_number   1
_cell_volume   626.712
_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  0.241  0.243  0.001  1.0
  Na  Na1  1  0.253  0.241  0.501  1.0
  Na  Na2  1  0.246  0.243  0.252  1.0
  Na  Na3  1  0.244  0.242  0.746  1.0
  Na  Na4  1  0.754  0.757  0.248  1.0
  Na  Na5  1  0.756  0.758  0.754  1.0
  Na  Na6  1  0.759  0.757  0.499  1.0
  Na  Na7  1  0.747  0.759  0.999  1.0
  Co  Co8  1  0.806  0.378  0.875  1.0
  Co  Co9  1  0.194  0.622  0.625  1.0
  Co  Co10  1  0.813  0.399  0.376  1.0
  Co  Co11  1  0.187  0.601  0.124  1.0
  Si  Si12  1  0.683  0.423  0.126  1.0
  Si  Si13  1  0.679  0.432  0.625  1.0
  Si  Si14  1  0.317  0.577  0.374  1.0
  Si  Si15  1  0.321  0.568  0.875  1.0
  C  C16  1  0.745  0.061  0.376  1.0
  C  C17  1  0.727  0.071  0.874  1.0
  C  C18  1  0.255  0.939  0.124  1.0
  C  C19  1  0.273  0.929  0.626  1.0
  O  O20  1  0.265  0.071  0.127  1.0
  O  O21  1  0.236  0.060  0.625  1.0
  O  O22  1  0.735  0.929  0.373  1.0
  O  O23  1  0.764  0.940  0.875  1.0
  O  O24  1  0.963  0.126  0.378  1.0
  O  O25  1  0.927  0.154  0.873  1.0
  O  O26  1  0.037  0.874  0.122  1.0
  O  O27  1  0.074  0.846  0.627  1.0
  O  O28  1  0.534  0.129  0.376  1.0
  O  O29  1  0.500  0.121  0.874  1.0
  O  O30  1  0.466  0.871  0.124  1.0
  O  O31  1  0.501  0.879  0.626  1.0
  O  O32  1  0.184  0.421  0.377  1.0
  O  O33  1  0.177  0.416  0.873  1.0
  O  O34  1  0.816  0.579  0.123  1.0
  O  O35  1  0.823  0.584  0.627  1.0
  O  O36  1  0.362  0.429  0.127  1.0
  O  O37  1  0.358  0.445  0.623  1.0
  O  O38  1  0.638  0.571  0.373  1.0
  O  O39  1  0.642  0.555  0.877  1.0
  O  O40  1  0.762  0.334  0.019  1.0
  O  O41  1  0.755  0.343  0.516  1.0
  O  O42  1  0.771  0.340  0.235  1.0
  O  O43  1  0.748  0.338  0.731  1.0
  O  O44  1  0.229  0.660  0.265  1.0
  O  O45  1  0.252  0.662  0.769  1.0
  O  O46  1  0.238  0.666  0.481  1.0
  O  O47  1  0.245  0.657  0.984  1.0
[/CIF]
.
The structure described by Na2CoSiCO7 crystallizes in the triclinic P-1 space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), one O(4), one O(6), one O(8), one O(9), and two equivalent O(11) atoms to form distorted NaO7 pentagonal bipyramids that share corners with two equivalent Na(1)O7 pentagonal bipyramids,  a cornercorner with one Co(2)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Co(1)O5 trigonal bipyramid,  an edgeedge with one Si(1)O4 tetrahedra,  a faceface with one Na(4)O7 pentagonal bipyramid, and  a faceface with one Co(1)O5 trigonal bipyramid. In the second Na site, Na(2) is bonded to one O(10), one O(2), one O(3), one O(5), one O(7), and two equivalent O(12) atoms to form distorted NaO7 pentagonal bipyramids that share corners with two equivalent Na(2)O7 pentagonal bipyramids,  a cornercorner with one Co(2)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Co(1)O5 trigonal bipyramid,  an edgeedge with one Na(4)O7 pentagonal bipyramid,  an edgeedge with one Co(2)O4 tetrahedra, and  an edgeedge with one Si(2)O4 tetrahedra. In the third Na site, Na(3) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(5), one O(7), one O(9), and two equivalent O(13) atoms. In the fourth Na site, Na(4) is bonded to one O(10), one O(2), one O(4), one O(6), one O(8), and two equivalent O(14) atoms to form distorted NaO7 pentagonal bipyramids that share corners with two equivalent Na(4)O7 pentagonal bipyramids, corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Co(1)O5 trigonal bipyramids,  an edgeedge with one Na(2)O7 pentagonal bipyramid,  an edgeedge with one Si(2)O4 tetrahedra,  a faceface with one Na(1)O7 pentagonal bipyramid, and  a faceface with one Co(1)O5 trigonal bipyramid. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(10), one O(11), one O(14), one O(4), and one O(8) atom to form distorted CoO5 trigonal bipyramids that share  a cornercorner with one Na(1)O7 pentagonal bipyramid,  a cornercorner with one Na(2)O7 pentagonal bipyramid, corners with two equivalent Na(4)O7 pentagonal bipyramids,  a cornercorner with one Si(1)O4 tetrahedra, corners with three equivalent Si(2)O4 tetrahedra,  a faceface with one Na(1)O7 pentagonal bipyramid, and  a faceface with one Na(4)O7 pentagonal bipyramid. In the second Co site, Co(2) is bonded to one O(12), one O(13), one O(7), and one O(9) atom to form distorted CoO4 tetrahedra that share  a cornercorner with one Na(1)O7 pentagonal bipyramid,  a cornercorner with one Na(2)O7 pentagonal bipyramid,  a cornercorner with one Si(2)O4 tetrahedra, corners with three equivalent Si(1)O4 tetrahedra, and  an edgeedge with one Na(2)O7 pentagonal bipyramid. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(11), one O(13), one O(7), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Na(1)O7 pentagonal bipyramid,  a cornercorner with one Na(2)O7 pentagonal bipyramid, corners with three equivalent Co(2)O4 tetrahedra,  a cornercorner with one Co(1)O5 trigonal bipyramid, and  an edgeedge with one Na(1)O7 pentagonal bipyramid. In the second Si site, Si(2) is bonded to one O(10), one O(12), one O(14), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Na(1)O7 pentagonal bipyramid,  a cornercorner with one Na(2)O7 pentagonal bipyramid, corners with two equivalent Na(4)O7 pentagonal bipyramids,  a cornercorner with one Co(2)O4 tetrahedra, corners with three equivalent Co(1)O5 trigonal bipyramids,  an edgeedge with one Na(2)O7 pentagonal bipyramid, and  an edgeedge with one Na(4)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(1), one O(3), and one O(5) atom. In the second C site, C(2) is bonded in a trigonal planar geometry to one O(2), one O(4), and one O(6) atom. 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(3), and one C(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(2), one Na(4), and one C(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Na(2), one Na(3), and one C(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Na(1), one Na(4), one Co(1), and one C(2) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Na(2), one Na(3), and one C(1) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Na(1), one Na(4), and one C(2) atom. In the seventh O site, O(7) is bonded in a distorted rectangular see-saw-like geometry to one Na(2), one Na(3), one Co(2), and one Si(1) atom. In the eighth O site, O(8) is bonded in a rectangular see-saw-like geometry to one Na(1), one Na(4), one Co(1), and one Si(2) atom. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to one Na(1), one Na(3), one Co(2), and one Si(1) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Na(2), one Na(4), one Co(1), and one Si(2) atom. In the eleventh O site, O(11) is bonded in a 2-coordinate geometry to two equivalent Na(1), one Co(1), and one Si(1) atom. In the twelfth O site, O(12) is bonded in a 2-coordinate geometry to two equivalent Na(2), one Co(2), and one Si(2) atom. In the thirteenth O site, O(13) is bonded in a 2-coordinate geometry to two equivalent Na(3), one Co(2), and one Si(1) atom. In the fourteenth O site, O(14) is bonded in a 2-coordinate geometry to two equivalent Na(4), one Co(1), and one Si(2) atom. is represented by the CIF file [CIF]
data_Na2CoSiCO7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.151
_cell_length_b   9.670
_cell_length_c   12.584
_cell_angle_alpha   89.896
_cell_angle_beta   90.019
_cell_angle_gamma   90.842
_symmetry_Int_Tables_number   1
_cell_volume   626.712
_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  0.241  0.243  0.001  1.0
  Na  Na1  1  0.253  0.241  0.501  1.0
  Na  Na2  1  0.246  0.243  0.252  1.0
  Na  Na3  1  0.244  0.242  0.746  1.0
  Na  Na4  1  0.754  0.757  0.248  1.0
  Na  Na5  1  0.756  0.758  0.754  1.0
  Na  Na6  1  0.759  0.757  0.499  1.0
  Na  Na7  1  0.747  0.759  0.999  1.0
  Co  Co8  1  0.806  0.378  0.875  1.0
  Co  Co9  1  0.194  0.622  0.625  1.0
  Co  Co10  1  0.813  0.399  0.376  1.0
  Co  Co11  1  0.187  0.601  0.124  1.0
  Si  Si12  1  0.683  0.423  0.126  1.0
  Si  Si13  1  0.679  0.432  0.625  1.0
  Si  Si14  1  0.317  0.577  0.374  1.0
  Si  Si15  1  0.321  0.568  0.875  1.0
  C  C16  1  0.745  0.061  0.376  1.0
  C  C17  1  0.727  0.071  0.874  1.0
  C  C18  1  0.255  0.939  0.124  1.0
  C  C19  1  0.273  0.929  0.626  1.0
  O  O20  1  0.265  0.071  0.127  1.0
  O  O21  1  0.236  0.060  0.625  1.0
  O  O22  1  0.735  0.929  0.373  1.0
  O  O23  1  0.764  0.940  0.875  1.0
  O  O24  1  0.963  0.126  0.378  1.0
  O  O25  1  0.927  0.154  0.873  1.0
  O  O26  1  0.037  0.874  0.122  1.0
  O  O27  1  0.074  0.846  0.627  1.0
  O  O28  1  0.534  0.129  0.376  1.0
  O  O29  1  0.500  0.121  0.874  1.0
  O  O30  1  0.466  0.871  0.124  1.0
  O  O31  1  0.501  0.879  0.626  1.0
  O  O32  1  0.184  0.421  0.377  1.0
  O  O33  1  0.177  0.416  0.873  1.0
  O  O34  1  0.816  0.579  0.123  1.0
  O  O35  1  0.823  0.584  0.627  1.0
  O  O36  1  0.362  0.429  0.127  1.0
  O  O37  1  0.358  0.445  0.623  1.0
  O  O38  1  0.638  0.571  0.373  1.0
  O  O39  1  0.642  0.555  0.877  1.0
  O  O40  1  0.762  0.334  0.019  1.0
  O  O41  1  0.755  0.343  0.516  1.0
  O  O42  1  0.771  0.340  0.235  1.0
  O  O43  1  0.748  0.338  0.731  1.0
  O  O44  1  0.229  0.660  0.265  1.0
  O  O45  1  0.252  0.662  0.769  1.0
  O  O46  1  0.238  0.666  0.481  1.0
  O  O47  1  0.245  0.657  0.984  1.0
[/CIF]
.