The structure described by Na2FeCPO7 crystallizes in the monoclinic Cm space group. There are five inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(16), one O(17), one O(6), one O(7), and two equivalent O(1) atoms. In the second Na site, Na(2) is bonded to one O(1), one O(10), one O(3), one O(4), one O(6), one O(7), and one O(8) atom to form distorted NaO7 pentagonal bipyramids that share  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra,  an edgeedge with one P(1)O4 tetrahedra,  a faceface with one Fe(2)O6 octahedra, and  a faceface with one Na(2)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 67°. In the third Na site, Na(3) is bonded to one O(12), one O(13), one O(14), one O(15), one O(16), one O(17), and one O(19) atom to form distorted NaO7 pentagonal bipyramids that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  an edgeedge with one Fe(3)O6 octahedra,  an edgeedge with one Na(3)O7 pentagonal bipyramid,  an edgeedge with one P(2)O4 tetrahedra, and  a faceface with one Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles are 65°. In the fourth Na site, Na(4) is bonded in a 6-coordinate geometry to one O(18), one O(19), one O(2), one O(5), and two equivalent O(15) atoms. In the fifth Na site, Na(5) is bonded in a 6-coordinate geometry to one O(18), one O(19), one O(3), one O(4), and two equivalent O(14) atoms. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(12), one O(2), one O(4), one O(9), and two equivalent O(7) atoms to form distorted FeO6 octahedra that share corners with two equivalent Na(3)O7 pentagonal bipyramids,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and edges with two equivalent Na(2)O7 pentagonal bipyramids. In the second Fe site, Fe(2) is bonded to one O(11), one O(3), one O(5), one O(8), and two equivalent O(6) atoms to form distorted FeO6 octahedra that share  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and faces with two equivalent Na(2)O7 pentagonal bipyramids. In the third Fe site, Fe(3) is bonded to one O(10), one O(13), one O(14), one O(15), one O(16), and one O(17) atom to form FeO6 octahedra that share  a cornercorner with one Na(2)O7 pentagonal bipyramid,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra,  an edgeedge with one Na(3)O7 pentagonal bipyramid, and  a faceface with one Na(3)O7 pentagonal bipyramid. There are three inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one O(18), one O(2), and one O(4) atom. In the second C site, C(2) is bonded in a trigonal planar geometry to one O(19), one O(3), and one O(5) atom. In the third C site, C(3) is bonded in a trigonal planar geometry to one O(1), one O(16), and one O(17) atom. There are three inequivalent P sites. In the first P site, P(1) is bonded to one O(10), one O(13), one O(6), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra,  a cornercorner with one Na(2)O7 pentagonal bipyramid,  a cornercorner with one Na(3)O7 pentagonal bipyramid, and  an edgeedge with one Na(2)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 33-44°. In the second P site, P(2) is bonded to one O(12), one O(8), and two equivalent O(15) atoms to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, corners with two equivalent Na(2)O7 pentagonal bipyramids, and edges with two equivalent Na(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 36-42°. In the third P site, P(3) is bonded to one O(11), one O(9), and two equivalent O(14) atoms to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, and corners with two equivalent Na(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 31-44°. There are nineteen inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Na(2), two equivalent Na(1), and one C(3) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Na(4), one Fe(1), and one C(1) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Na(5), two equivalent Na(2), one Fe(2), and one C(2) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Na(5), two equivalent Na(2), one Fe(1), and one C(1) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Na(4), one Fe(2), and one C(2) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Fe(2), and one P(1) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Fe(1), and one P(1) atom. In the eighth O site, O(8) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na(2), one Fe(2), and one P(2) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(3) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Na(2), one Fe(3), and one P(1) atom. In the eleventh O site, O(11) is bonded in a distorted bent 150 degrees geometry to one Fe(2) and one P(3) atom. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to two equivalent Na(3), one Fe(1), and one P(2) atom. In the thirteenth O site, O(13) is bonded in a 3-coordinate geometry to one Na(3), one Fe(3), and one P(1) atom. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Na(3), one Na(5), one Fe(3), and one P(3) atom. In the fifteenth O site, O(15) is bonded in a 4-coordinate geometry to one Na(3), one Na(4), one Fe(3), and one P(2) atom. In the sixteenth O site, O(16) is bonded in a 4-coordinate geometry to one Na(1), one Na(3), one Fe(3), and one C(3) atom. In the seventeenth O site, O(17) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(3), one Fe(3), and one C(3) atom. In the eighteenth O site, O(18) is bonded in a 3-coordinate geometry to one Na(4), one Na(5), and one C(1) atom. In the nineteenth O site, O(19) is bonded in a 5-coordinate geometry to one Na(4), one Na(5), two equivalent Na(3), and one C(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na2FePCO7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.385
_cell_length_b   8.385
_cell_length_c   10.347
_cell_angle_alpha   71.706
_cell_angle_beta   71.706
_cell_angle_gamma   102.212
_symmetry_Int_Tables_number   1
_cell_volume   615.807
_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  0.308  0.788  0.920  1.0
  Na  Na1  1  0.788  0.308  0.920  1.0
  Na  Na2  1  0.251  0.523  0.730  1.0
  Na  Na3  1  0.523  0.251  0.730  1.0
  Na  Na4  1  0.742  0.993  0.258  1.0
  Na  Na5  1  0.993  0.742  0.258  1.0
  Na  Na6  1  0.683  0.683  0.083  1.0
  Na  Na7  1  0.210  0.210  0.088  1.0
  Fe  Fe8  1  0.695  0.695  0.659  1.0
  Fe  Fe9  1  0.180  0.180  0.651  1.0
  Fe  Fe10  1  0.812  0.311  0.346  1.0
  Fe  Fe11  1  0.311  0.812  0.346  1.0
  P  P12  1  0.444  0.944  0.576  1.0
  P  P13  1  0.944  0.444  0.576  1.0
  P  P14  1  0.560  0.560  0.425  1.0
  P  P15  1  0.054  0.054  0.425  1.0
  C  C16  1  0.517  0.517  0.936  1.0
  C  C17  1  0.026  0.026  0.935  1.0
  C  C18  1  0.982  0.473  0.065  1.0
  C  C19  1  0.473  0.982  0.065  1.0
  O  O20  1  0.070  0.553  0.925  1.0
  O  O21  1  0.553  0.070  0.925  1.0
  O  O22  1  0.661  0.661  0.872  1.0
  O  O23  1  0.170  0.170  0.873  1.0
  O  O24  1  0.467  0.467  0.841  1.0
  O  O25  1  0.976  0.976  0.843  1.0
  O  O26  1  0.027  0.338  0.673  1.0
  O  O27  1  0.338  0.027  0.673  1.0
  O  O28  1  0.505  0.817  0.679  1.0
  O  O29  1  0.817  0.505  0.679  1.0
  O  O30  1  0.407  0.407  0.569  1.0
  O  O31  1  0.903  0.903  0.568  1.0
  O  O32  1  0.827  0.322  0.529  1.0
  O  O33  1  0.322  0.827  0.529  1.0
  O  O34  1  0.174  0.174  0.470  1.0
  O  O35  1  0.682  0.682  0.470  1.0
  O  O36  1  0.091  0.602  0.433  1.0
  O  O37  1  0.602  0.091  0.433  1.0
  O  O38  1  0.165  0.977  0.324  1.0
  O  O39  1  0.490  0.680  0.325  1.0
  O  O40  1  0.680  0.490  0.325  1.0
  O  O41  1  0.977  0.165  0.324  1.0
  O  O42  1  0.023  0.531  0.159  1.0
  O  O43  1  0.531  0.023  0.159  1.0
  O  O44  1  0.842  0.325  0.128  1.0
  O  O45  1  0.325  0.842  0.128  1.0
  O  O46  1  0.435  0.435  0.075  1.0
  O  O47  1  0.941  0.941  0.077  1.0
[/CIF]
.
The structure described by Na2FeCPO7 crystallizes in the monoclinic Cm space group. There are five inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(16), one O(17), one O(6), one O(7), and two equivalent O(1) atoms. In the second Na site, Na(2) is bonded to one O(1), one O(10), one O(3), one O(4), one O(6), one O(7), and one O(8) atom to form distorted NaO7 pentagonal bipyramids that share  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra,  an edgeedge with one P(1)O4 tetrahedra,  a faceface with one Fe(2)O6 octahedra, and  a faceface with one Na(2)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 67°. In the third Na site, Na(3) is bonded to one O(12), one O(13), one O(14), one O(15), one O(16), one O(17), and one O(19) atom to form distorted NaO7 pentagonal bipyramids that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  an edgeedge with one Fe(3)O6 octahedra,  an edgeedge with one Na(3)O7 pentagonal bipyramid,  an edgeedge with one P(2)O4 tetrahedra, and  a faceface with one Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles are 65°. In the fourth Na site, Na(4) is bonded in a 6-coordinate geometry to one O(18), one O(19), one O(2), one O(5), and two equivalent O(15) atoms. In the fifth Na site, Na(5) is bonded in a 6-coordinate geometry to one O(18), one O(19), one O(3), one O(4), and two equivalent O(14) atoms. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(12), one O(2), one O(4), one O(9), and two equivalent O(7) atoms to form distorted FeO6 octahedra that share corners with two equivalent Na(3)O7 pentagonal bipyramids,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and edges with two equivalent Na(2)O7 pentagonal bipyramids. In the second Fe site, Fe(2) is bonded to one O(11), one O(3), one O(5), one O(8), and two equivalent O(6) atoms to form distorted FeO6 octahedra that share  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and faces with two equivalent Na(2)O7 pentagonal bipyramids. In the third Fe site, Fe(3) is bonded to one O(10), one O(13), one O(14), one O(15), one O(16), and one O(17) atom to form FeO6 octahedra that share  a cornercorner with one Na(2)O7 pentagonal bipyramid,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra,  an edgeedge with one Na(3)O7 pentagonal bipyramid, and  a faceface with one Na(3)O7 pentagonal bipyramid. There are three inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one O(18), one O(2), and one O(4) atom. In the second C site, C(2) is bonded in a trigonal planar geometry to one O(19), one O(3), and one O(5) atom. In the third C site, C(3) is bonded in a trigonal planar geometry to one O(1), one O(16), and one O(17) atom. There are three inequivalent P sites. In the first P site, P(1) is bonded to one O(10), one O(13), one O(6), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra,  a cornercorner with one Na(2)O7 pentagonal bipyramid,  a cornercorner with one Na(3)O7 pentagonal bipyramid, and  an edgeedge with one Na(2)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 33-44°. In the second P site, P(2) is bonded to one O(12), one O(8), and two equivalent O(15) atoms to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, corners with two equivalent Na(2)O7 pentagonal bipyramids, and edges with two equivalent Na(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 36-42°. In the third P site, P(3) is bonded to one O(11), one O(9), and two equivalent O(14) atoms to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, and corners with two equivalent Na(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 31-44°. There are nineteen inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Na(2), two equivalent Na(1), and one C(3) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Na(4), one Fe(1), and one C(1) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Na(5), two equivalent Na(2), one Fe(2), and one C(2) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Na(5), two equivalent Na(2), one Fe(1), and one C(1) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Na(4), one Fe(2), and one C(2) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Fe(2), and one P(1) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Fe(1), and one P(1) atom. In the eighth O site, O(8) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na(2), one Fe(2), and one P(2) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(3) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Na(2), one Fe(3), and one P(1) atom. In the eleventh O site, O(11) is bonded in a distorted bent 150 degrees geometry to one Fe(2) and one P(3) atom. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to two equivalent Na(3), one Fe(1), and one P(2) atom. In the thirteenth O site, O(13) is bonded in a 3-coordinate geometry to one Na(3), one Fe(3), and one P(1) atom. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Na(3), one Na(5), one Fe(3), and one P(3) atom. In the fifteenth O site, O(15) is bonded in a 4-coordinate geometry to one Na(3), one Na(4), one Fe(3), and one P(2) atom. In the sixteenth O site, O(16) is bonded in a 4-coordinate geometry to one Na(1), one Na(3), one Fe(3), and one C(3) atom. In the seventeenth O site, O(17) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(3), one Fe(3), and one C(3) atom. In the eighteenth O site, O(18) is bonded in a 3-coordinate geometry to one Na(4), one Na(5), and one C(1) atom. In the nineteenth O site, O(19) is bonded in a 5-coordinate geometry to one Na(4), one Na(5), two equivalent Na(3), and one C(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na2FePCO7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.385
_cell_length_b   8.385
_cell_length_c   10.347
_cell_angle_alpha   71.706
_cell_angle_beta   71.706
_cell_angle_gamma   102.212
_symmetry_Int_Tables_number   1
_cell_volume   615.807
_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  0.308  0.788  0.920  1.0
  Na  Na1  1  0.788  0.308  0.920  1.0
  Na  Na2  1  0.251  0.523  0.730  1.0
  Na  Na3  1  0.523  0.251  0.730  1.0
  Na  Na4  1  0.742  0.993  0.258  1.0
  Na  Na5  1  0.993  0.742  0.258  1.0
  Na  Na6  1  0.683  0.683  0.083  1.0
  Na  Na7  1  0.210  0.210  0.088  1.0
  Fe  Fe8  1  0.695  0.695  0.659  1.0
  Fe  Fe9  1  0.180  0.180  0.651  1.0
  Fe  Fe10  1  0.812  0.311  0.346  1.0
  Fe  Fe11  1  0.311  0.812  0.346  1.0
  P  P12  1  0.444  0.944  0.576  1.0
  P  P13  1  0.944  0.444  0.576  1.0
  P  P14  1  0.560  0.560  0.425  1.0
  P  P15  1  0.054  0.054  0.425  1.0
  C  C16  1  0.517  0.517  0.936  1.0
  C  C17  1  0.026  0.026  0.935  1.0
  C  C18  1  0.982  0.473  0.065  1.0
  C  C19  1  0.473  0.982  0.065  1.0
  O  O20  1  0.070  0.553  0.925  1.0
  O  O21  1  0.553  0.070  0.925  1.0
  O  O22  1  0.661  0.661  0.872  1.0
  O  O23  1  0.170  0.170  0.873  1.0
  O  O24  1  0.467  0.467  0.841  1.0
  O  O25  1  0.976  0.976  0.843  1.0
  O  O26  1  0.027  0.338  0.673  1.0
  O  O27  1  0.338  0.027  0.673  1.0
  O  O28  1  0.505  0.817  0.679  1.0
  O  O29  1  0.817  0.505  0.679  1.0
  O  O30  1  0.407  0.407  0.569  1.0
  O  O31  1  0.903  0.903  0.568  1.0
  O  O32  1  0.827  0.322  0.529  1.0
  O  O33  1  0.322  0.827  0.529  1.0
  O  O34  1  0.174  0.174  0.470  1.0
  O  O35  1  0.682  0.682  0.470  1.0
  O  O36  1  0.091  0.602  0.433  1.0
  O  O37  1  0.602  0.091  0.433  1.0
  O  O38  1  0.165  0.977  0.324  1.0
  O  O39  1  0.490  0.680  0.325  1.0
  O  O40  1  0.680  0.490  0.325  1.0
  O  O41  1  0.977  0.165  0.324  1.0
  O  O42  1  0.023  0.531  0.159  1.0
  O  O43  1  0.531  0.023  0.159  1.0
  O  O44  1  0.842  0.325  0.128  1.0
  O  O45  1  0.325  0.842  0.128  1.0
  O  O46  1  0.435  0.435  0.075  1.0
  O  O47  1  0.941  0.941  0.077  1.0
[/CIF]
.