The structure described by Na2FeCPO7 crystallizes in the monoclinic P2_1/c 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), one O(4), one O(5), and two equivalent O(1) atoms. In the second Na site, Na(2) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form distorted NaO7 pentagonal bipyramids that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra,  an edgeedge with one P(1)O4 tetrahedra, and  a faceface with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles are 66°. Fe(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form FeO6 octahedra that share  a cornercorner with one Na(2)O7 pentagonal bipyramid, corners with four equivalent P(1)O4 tetrahedra,  an edgeedge with one Na(2)O7 pentagonal bipyramid, and  a faceface with one Na(2)O7 pentagonal bipyramid. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. P(1) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with four equivalent Fe(1)O6 octahedra, corners with two equivalent Na(2)O7 pentagonal bipyramids, and  an edgeedge with one Na(2)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 34-42°. There are seven inequivalent O sites. In the first O site, O(7) is bonded in a 3-coordinate geometry to one Na(2), one Fe(1), and one P(1) atom. In the second O site, O(1) is bonded in a 4-coordinate geometry to one Na(2), two equivalent Na(1), and one C(1) atom. In the third O site, O(2) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Fe(1), and one C(1) atom. In the fourth O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Fe(1), and one C(1) atom. In the fifth O site, O(4) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Fe(1), and one P(1) atom. In the sixth O site, O(5) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Fe(1), and one P(1) atom. In the seventh O site, O(6) is bonded in a 3-coordinate geometry to one Na(2), one Fe(1), and one P(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na2FePCO7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.531
_cell_length_b   10.363
_cell_length_c   10.496
_cell_angle_alpha   59.789
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   613.874
_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  0.261  0.080  0.577  1.0
  Na  Na1  1  0.239  0.080  0.077  1.0
  Na  Na2  1  0.486  0.264  0.741  1.0
  Na  Na3  1  0.014  0.264  0.241  1.0
  Na  Na4  1  0.986  0.736  0.759  1.0
  Na  Na5  1  0.514  0.736  0.259  1.0
  Na  Na6  1  0.761  0.920  0.923  1.0
  Na  Na7  1  0.739  0.920  0.423  1.0
  Fe  Fe8  1  0.753  0.345  0.935  1.0
  Fe  Fe9  1  0.747  0.345  0.435  1.0
  Fe  Fe10  1  0.253  0.655  0.565  1.0
  Fe  Fe11  1  0.247  0.655  0.065  1.0
  P  P12  1  0.252  0.424  0.933  1.0
  P  P13  1  0.248  0.424  0.433  1.0
  P  P14  1  0.752  0.576  0.567  1.0
  P  P15  1  0.748  0.576  0.067  1.0
  C  C16  1  0.757  0.065  0.603  1.0
  C  C17  1  0.743  0.065  0.103  1.0
  C  C18  1  0.257  0.935  0.897  1.0
  C  C19  1  0.243  0.935  0.397  1.0
  O  O20  1  0.262  0.076  0.813  1.0
  O  O21  1  0.238  0.076  0.313  1.0
  O  O22  1  0.734  0.129  0.958  1.0
  O  O23  1  0.766  0.129  0.458  1.0
  O  O24  1  0.740  0.157  0.653  1.0
  O  O25  1  0.760  0.157  0.153  1.0
  O  O26  1  0.061  0.322  0.962  1.0
  O  O27  1  0.439  0.326  0.946  1.0
  O  O28  1  0.061  0.326  0.446  1.0
  O  O29  1  0.439  0.322  0.462  1.0
  O  O30  1  0.742  0.432  0.719  1.0
  O  O31  1  0.758  0.432  0.219  1.0
  O  O32  1  0.248  0.469  0.555  1.0
  O  O33  1  0.252  0.469  0.055  1.0
  O  O34  1  0.748  0.531  0.945  1.0
  O  O35  1  0.752  0.531  0.445  1.0
  O  O36  1  0.242  0.568  0.781  1.0
  O  O37  1  0.258  0.568  0.281  1.0
  O  O38  1  0.561  0.678  0.538  1.0
  O  O39  1  0.939  0.674  0.554  1.0
  O  O40  1  0.939  0.678  0.038  1.0
  O  O41  1  0.561  0.674  0.054  1.0
  O  O42  1  0.240  0.843  0.847  1.0
  O  O43  1  0.260  0.843  0.347  1.0
  O  O44  1  0.234  0.871  0.542  1.0
  O  O45  1  0.266  0.871  0.042  1.0
  O  O46  1  0.762  0.924  0.687  1.0
  O  O47  1  0.738  0.924  0.187  1.0
[/CIF]
.
The structure described by Na2FeCPO7 crystallizes in the monoclinic P2_1/c 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), one O(4), one O(5), and two equivalent O(1) atoms. In the second Na site, Na(2) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form distorted NaO7 pentagonal bipyramids that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra,  an edgeedge with one P(1)O4 tetrahedra, and  a faceface with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles are 66°. Fe(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form FeO6 octahedra that share  a cornercorner with one Na(2)O7 pentagonal bipyramid, corners with four equivalent P(1)O4 tetrahedra,  an edgeedge with one Na(2)O7 pentagonal bipyramid, and  a faceface with one Na(2)O7 pentagonal bipyramid. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. P(1) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with four equivalent Fe(1)O6 octahedra, corners with two equivalent Na(2)O7 pentagonal bipyramids, and  an edgeedge with one Na(2)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 34-42°. There are seven inequivalent O sites. In the first O site, O(7) is bonded in a 3-coordinate geometry to one Na(2), one Fe(1), and one P(1) atom. In the second O site, O(1) is bonded in a 4-coordinate geometry to one Na(2), two equivalent Na(1), and one C(1) atom. In the third O site, O(2) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Fe(1), and one C(1) atom. In the fourth O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Fe(1), and one C(1) atom. In the fifth O site, O(4) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Fe(1), and one P(1) atom. In the sixth O site, O(5) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Fe(1), and one P(1) atom. In the seventh O site, O(6) is bonded in a 3-coordinate geometry to one Na(2), one Fe(1), and one P(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na2FePCO7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.531
_cell_length_b   10.363
_cell_length_c   10.496
_cell_angle_alpha   59.789
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   613.874
_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  0.261  0.080  0.577  1.0
  Na  Na1  1  0.239  0.080  0.077  1.0
  Na  Na2  1  0.486  0.264  0.741  1.0
  Na  Na3  1  0.014  0.264  0.241  1.0
  Na  Na4  1  0.986  0.736  0.759  1.0
  Na  Na5  1  0.514  0.736  0.259  1.0
  Na  Na6  1  0.761  0.920  0.923  1.0
  Na  Na7  1  0.739  0.920  0.423  1.0
  Fe  Fe8  1  0.753  0.345  0.935  1.0
  Fe  Fe9  1  0.747  0.345  0.435  1.0
  Fe  Fe10  1  0.253  0.655  0.565  1.0
  Fe  Fe11  1  0.247  0.655  0.065  1.0
  P  P12  1  0.252  0.424  0.933  1.0
  P  P13  1  0.248  0.424  0.433  1.0
  P  P14  1  0.752  0.576  0.567  1.0
  P  P15  1  0.748  0.576  0.067  1.0
  C  C16  1  0.757  0.065  0.603  1.0
  C  C17  1  0.743  0.065  0.103  1.0
  C  C18  1  0.257  0.935  0.897  1.0
  C  C19  1  0.243  0.935  0.397  1.0
  O  O20  1  0.262  0.076  0.813  1.0
  O  O21  1  0.238  0.076  0.313  1.0
  O  O22  1  0.734  0.129  0.958  1.0
  O  O23  1  0.766  0.129  0.458  1.0
  O  O24  1  0.740  0.157  0.653  1.0
  O  O25  1  0.760  0.157  0.153  1.0
  O  O26  1  0.061  0.322  0.962  1.0
  O  O27  1  0.439  0.326  0.946  1.0
  O  O28  1  0.061  0.326  0.446  1.0
  O  O29  1  0.439  0.322  0.462  1.0
  O  O30  1  0.742  0.432  0.719  1.0
  O  O31  1  0.758  0.432  0.219  1.0
  O  O32  1  0.248  0.469  0.555  1.0
  O  O33  1  0.252  0.469  0.055  1.0
  O  O34  1  0.748  0.531  0.945  1.0
  O  O35  1  0.752  0.531  0.445  1.0
  O  O36  1  0.242  0.568  0.781  1.0
  O  O37  1  0.258  0.568  0.281  1.0
  O  O38  1  0.561  0.678  0.538  1.0
  O  O39  1  0.939  0.674  0.554  1.0
  O  O40  1  0.939  0.678  0.038  1.0
  O  O41  1  0.561  0.674  0.054  1.0
  O  O42  1  0.240  0.843  0.847  1.0
  O  O43  1  0.260  0.843  0.347  1.0
  O  O44  1  0.234  0.871  0.542  1.0
  O  O45  1  0.266  0.871  0.042  1.0
  O  O46  1  0.762  0.924  0.687  1.0
  O  O47  1  0.738  0.924  0.187  1.0
[/CIF]
.