The material described by Na2CoP2O7 crystallizes in the triclinic P1 space group. There are eight inequivalent Na sites. In the first Na site, Na(1) is bonded in a 8-coordinate geometry to one O(1), one O(12), one O(13), one O(17), one O(19), one O(24), one O(26), and one O(28) atom. In the second Na site, Na(2) is bonded in a see-saw-like geometry to one O(15), one O(18), one O(25), and one O(8) atom. In the third Na site, Na(3) is bonded in a 6-coordinate geometry to one O(15), one O(16), one O(18), one O(20), one O(6), and one O(9) atom. In the fourth Na site, Na(4) is bonded in a 6-coordinate geometry to one O(11), one O(16), one O(2), one O(22), one O(26), and one O(3) atom. In the fifth Na site, Na(5) is bonded in a 5-coordinate geometry to one O(11), one O(19), one O(2), one O(4), and one O(7) atom. In the sixth Na site, Na(6) is bonded to one O(14), one O(15), one O(28), one O(5), one O(8), and one O(9) atom to form distorted NaO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra,  an edgeedge with one Co(1)O6 octahedra, and  an edgeedge with one Co(3)O6 octahedra. In the seventh Na site, Na(7) is bonded in a see-saw-like geometry to one O(18), one O(23), one O(8), and one O(9) atom. In the eighth Na site, Na(8) is bonded in a 6-coordinate geometry to one O(1), one O(12), one O(17), one O(24), one O(4), and one O(6) atom. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(13), one O(24), one O(25), one O(28), and one O(8) atom to form CoO6 octahedra that share  a cornercorner with one Co(4)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra,  a cornercorner with one P(8)O4 tetrahedra,  an edgeedge with one Na(6)O6 octahedra, and  an edgeedge with one P(4)O4 tetrahedra. The corner-sharing octahedral tilt angles are 62°. In the second Co site, Co(2) is bonded to one O(12), one O(17), one O(18), one O(21), one O(23), and one O(6) atom to form CoO6 octahedra that share  a cornercorner with one Co(3)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra,  a cornercorner with one P(8)O4 tetrahedra, and  an edgeedge with one P(7)O4 tetrahedra. The corner-sharing octahedral tilt angles are 62°. In the third Co site, Co(3) is bonded to one O(11), one O(14), one O(2), one O(21), one O(4), and one O(5) atom to form CoO6 octahedra that share  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and  an edgeedge with one Na(6)O6 octahedra. The corner-sharing octahedral tilt angles are 62°. In the fourth Co site, Co(4) is bonded to one O(13), one O(16), one O(19), one O(20), one O(26), and one O(7) atom to form CoO6 octahedra that share  a cornercorner with one Co(1)O6 octahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra,  a cornercorner with one P(8)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 62°. There are eight inequivalent P sites. In the first P site, P(1) is bonded to one O(27), one O(4), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Na(6)O6 octahedra,  a cornercorner with one Co(2)O6 octahedra, corners with two equivalent Co(3)O6 octahedra, and  a cornercorner with one P(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 41-64°. In the second P site, P(2) is bonded to one O(10), one O(16), one O(26), and one O(28) atom to form PO4 tetrahedra that share  a cornercorner with one Na(6)O6 octahedra,  a cornercorner with one Co(1)O6 octahedra, corners with two equivalent Co(4)O6 octahedra, and  a cornercorner with one P(7)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 40-55°. In the third P site, P(3) is bonded to one O(12), one O(2), one O(3), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Na(6)O6 octahedra,  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one Co(3)O6 octahedra, and  a cornercorner with one P(8)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 45-53°. In the fourth P site, P(4) is bonded to one O(13), one O(14), one O(27), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Co(3)O6 octahedra,  a cornercorner with one Co(4)O6 octahedra, corners with two equivalent Na(6)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and  an edgeedge with one Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-64°. In the fifth P site, P(5) is bonded to one O(11), one O(17), one O(22), and one O(25) atom to form PO4 tetrahedra that share  a cornercorner with one Co(1)O6 octahedra,  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one Co(3)O6 octahedra, and  a cornercorner with one P(6)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 40-45°. In the sixth P site, P(6) is bonded to one O(15), one O(22), one O(24), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Na(6)O6 octahedra,  a cornercorner with one Co(1)O6 octahedra,  a cornercorner with one Co(4)O6 octahedra, and  a cornercorner with one P(5)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 45-66°. In the seventh P site, P(7) is bonded to one O(10), one O(18), one O(20), and one O(21) atom to form PO4 tetrahedra that share  a cornercorner with one Co(3)O6 octahedra,  a cornercorner with one Co(4)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, and  an edgeedge with one Co(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-50°. In the eighth P site, P(8) is bonded to one O(1), one O(19), one O(23), and one O(3) atom to form PO4 tetrahedra that share  a cornercorner with one Co(1)O6 octahedra,  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one Co(4)O6 octahedra, and  a cornercorner with one P(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 41-47°. There are twenty-eight inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one Na(8), one Co(1), and one P(8) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Na(4), one Na(5), one Co(3), and one P(3) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Na(4), one P(3), and one P(8) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Na(5), one Na(8), one Co(3), and one P(1) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Na(6), one Co(3), and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Na(3), one Na(8), one Co(2), and one P(1) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Na(5), one Co(4), and one P(6) atom. In the eighth O site, O(8) is bonded to one Na(2), one Na(6), one Na(7), one Co(1), and one P(4) atom to form distorted ONa3CoP trigonal bipyramids that share corners with two equivalent O(15)Na3P tetrahedra,  an edgeedge with one O(9)Na3P tetrahedra, and  an edgeedge with one O(18)Na3CoP trigonal bipyramid. In the ninth O site, O(9) is bonded to one Na(3), one Na(6), one Na(7), and one P(3) atom to form distorted ONa3P tetrahedra that share corners with two equivalent O(18)Na3CoP trigonal bipyramids,  an edgeedge with one O(15)Na3P tetrahedra, and  an edgeedge with one O(8)Na3CoP trigonal bipyramid. In the tenth O site, O(10) is bonded in a distorted bent 150 degrees geometry to one P(2) and one P(7) atom. In the eleventh O site, O(11) is bonded in a distorted rectangular see-saw-like geometry to one Na(4), one Na(5), one Co(3), and one P(5) atom. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to one Na(1), one Na(8), one Co(2), and one P(3) atom. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to one Na(1), one Co(1), one Co(4), and one P(4) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal planar geometry to one Na(6), one Co(3), and one P(4) atom. In the fifteenth O site, O(15) is bonded to one Na(2), one Na(3), one Na(6), and one P(6) atom to form distorted ONa3P tetrahedra that share corners with two equivalent O(8)Na3CoP trigonal bipyramids,  an edgeedge with one O(9)Na3P tetrahedra, and  an edgeedge with one O(18)Na3CoP trigonal bipyramid. In the sixteenth O site, O(16) is bonded in a 4-coordinate geometry to one Na(3), one Na(4), one Co(4), and one P(2) atom. In the seventeenth O site, O(17) is bonded in a 4-coordinate geometry to one Na(1), one Na(8), one Co(2), and one P(5) atom. In the eighteenth O site, O(18) is bonded to one Na(2), one Na(3), one Na(7), one Co(2), and one P(7) atom to form distorted ONa3CoP trigonal bipyramids that share corners with two equivalent O(9)Na3P tetrahedra,  an edgeedge with one O(15)Na3P tetrahedra, and  an edgeedge with one O(8)Na3CoP trigonal bipyramid. In the nineteenth O site, O(19) is bonded in a 4-coordinate geometry to one Na(1), one Na(5), one Co(4), and one P(8) atom. In the twentieth O site, O(20) is bonded in a distorted trigonal planar geometry to one Na(3), one Co(4), and one P(7) atom. In the twenty-first O site, O(21) is bonded in a 3-coordinate geometry to one Co(2), one Co(3), and one P(7) atom. In the twenty-second O site, O(22) is bonded in a distorted trigonal planar geometry to one Na(4), one P(5), and one P(6) atom. In the twenty-third O site, O(23) is bonded in a distorted trigonal planar geometry to one Na(7), one Co(2), and one P(8) atom. In the twenty-fourth O site, O(24) is bonded in a 4-coordinate geometry to one Na(1), one Na(8), one Co(1), and one P(6) atom. In the twenty-fifth O site, O(25) is bonded in a 3-coordinate geometry to one Na(2), one Co(1), and one P(5) atom. In the twenty-sixth O site, O(26) is bonded in a distorted trigonal pyramidal geometry to one Na(1), one Na(4), one Co(4), and one P(2) atom. In the twenty-seventh O site, O(27) is bonded in a bent 120 degrees geometry to one P(1) and one P(4) atom. In the twenty-eighth O site, O(28) is bonded in a 4-coordinate geometry to one Na(1), one Na(6), one Co(1), and one P(2) atom. is represented by the CIF file [CIF]
data_Na2CoP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.546
_cell_length_b   9.553
_cell_length_c   11.069
_cell_angle_alpha   64.679
_cell_angle_beta   85.925
_cell_angle_gamma   73.428
_symmetry_Int_Tables_number   1
_cell_volume   598.689
_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  0.780  0.148  0.890  1.0
  Na  Na1  1  0.603  0.877  0.650  1.0
  Na  Na2  1  0.035  0.813  0.478  1.0
  Na  Na3  1  0.844  0.488  0.946  1.0
  Na  Na4  1  0.394  0.506  0.034  1.0
  Na  Na5  1  0.968  0.184  0.522  1.0
  Na  Na6  1  0.389  0.124  0.349  1.0
  Na  Na7  1  0.174  0.854  0.097  1.0
  Co  Co8  1  0.281  0.105  0.781  1.0
  Co  Co9  1  0.720  0.888  0.224  1.0
  Co  Co10  1  0.643  0.499  0.266  1.0
  Co  Co11  1  0.363  0.493  0.740  1.0
  P  P12  1  0.120  0.545  0.316  1.0
  P  P13  1  0.883  0.445  0.690  1.0
  P  P14  1  0.922  0.178  0.209  1.0
  P  P15  1  0.423  0.297  0.543  1.0
  P  P16  1  0.707  0.806  0.963  1.0
  P  P17  1  0.079  0.817  0.792  1.0
  P  P18  1  0.579  0.697  0.461  1.0
  P  P19  1  0.299  0.183  0.041  1.0
  O  O20  1  0.227  0.101  0.967  1.0
  O  O21  1  0.722  0.321  0.186  1.0
  O  O22  1  0.084  0.270  0.098  1.0
  O  O23  1  0.308  0.538  0.224  1.0
  O  O24  1  0.968  0.455  0.305  1.0
  O  O25  1  0.016  0.718  0.300  1.0
  O  O26  1  0.283  0.679  0.809  1.0
  O  O27  1  0.358  0.144  0.563  1.0
  O  O28  1  0.036  0.097  0.347  1.0
  O  O29  1  0.783  0.545  0.537  1.0
  O  O30  1  0.621  0.663  0.049  1.0
  O  O31  1  0.886  0.060  0.159  1.0
  O  O32  1  0.444  0.292  0.684  1.0
  O  O33  1  0.614  0.318  0.458  1.0
  O  O34  1  0.959  0.898  0.656  1.0
  O  O35  1  0.035  0.529  0.712  1.0
  O  O36  1  0.778  0.886  0.039  1.0
  O  O37  1  0.639  0.851  0.441  1.0
  O  O38  1  0.388  0.323  0.950  1.0
  O  O39  1  0.389  0.673  0.547  1.0
  O  O40  1  0.563  0.699  0.322  1.0
  O  O41  1  0.924  0.721  0.905  1.0
  O  O42  1  0.438  0.063  0.168  1.0
  O  O43  1  0.114  0.934  0.843  1.0
  O  O44  1  0.567  0.929  0.836  1.0
  O  O45  1  0.695  0.451  0.783  1.0
  O  O46  1  0.224  0.452  0.469  1.0
  O  O47  1  0.984  0.274  0.703  1.0
[/CIF]
.
The material described by Na2CoP2O7 crystallizes in the triclinic P1 space group. There are eight inequivalent Na sites. In the first Na site, Na(1) is bonded in a 8-coordinate geometry to one O(1), one O(12), one O(13), one O(17), one O(19), one O(24), one O(26), and one O(28) atom. In the second Na site, Na(2) is bonded in a see-saw-like geometry to one O(15), one O(18), one O(25), and one O(8) atom. In the third Na site, Na(3) is bonded in a 6-coordinate geometry to one O(15), one O(16), one O(18), one O(20), one O(6), and one O(9) atom. In the fourth Na site, Na(4) is bonded in a 6-coordinate geometry to one O(11), one O(16), one O(2), one O(22), one O(26), and one O(3) atom. In the fifth Na site, Na(5) is bonded in a 5-coordinate geometry to one O(11), one O(19), one O(2), one O(4), and one O(7) atom. In the sixth Na site, Na(6) is bonded to one O(14), one O(15), one O(28), one O(5), one O(8), and one O(9) atom to form distorted NaO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra,  an edgeedge with one Co(1)O6 octahedra, and  an edgeedge with one Co(3)O6 octahedra. In the seventh Na site, Na(7) is bonded in a see-saw-like geometry to one O(18), one O(23), one O(8), and one O(9) atom. In the eighth Na site, Na(8) is bonded in a 6-coordinate geometry to one O(1), one O(12), one O(17), one O(24), one O(4), and one O(6) atom. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(13), one O(24), one O(25), one O(28), and one O(8) atom to form CoO6 octahedra that share  a cornercorner with one Co(4)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra,  a cornercorner with one P(8)O4 tetrahedra,  an edgeedge with one Na(6)O6 octahedra, and  an edgeedge with one P(4)O4 tetrahedra. The corner-sharing octahedral tilt angles are 62°. In the second Co site, Co(2) is bonded to one O(12), one O(17), one O(18), one O(21), one O(23), and one O(6) atom to form CoO6 octahedra that share  a cornercorner with one Co(3)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra,  a cornercorner with one P(8)O4 tetrahedra, and  an edgeedge with one P(7)O4 tetrahedra. The corner-sharing octahedral tilt angles are 62°. In the third Co site, Co(3) is bonded to one O(11), one O(14), one O(2), one O(21), one O(4), and one O(5) atom to form CoO6 octahedra that share  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and  an edgeedge with one Na(6)O6 octahedra. The corner-sharing octahedral tilt angles are 62°. In the fourth Co site, Co(4) is bonded to one O(13), one O(16), one O(19), one O(20), one O(26), and one O(7) atom to form CoO6 octahedra that share  a cornercorner with one Co(1)O6 octahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra,  a cornercorner with one P(8)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 62°. There are eight inequivalent P sites. In the first P site, P(1) is bonded to one O(27), one O(4), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Na(6)O6 octahedra,  a cornercorner with one Co(2)O6 octahedra, corners with two equivalent Co(3)O6 octahedra, and  a cornercorner with one P(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 41-64°. In the second P site, P(2) is bonded to one O(10), one O(16), one O(26), and one O(28) atom to form PO4 tetrahedra that share  a cornercorner with one Na(6)O6 octahedra,  a cornercorner with one Co(1)O6 octahedra, corners with two equivalent Co(4)O6 octahedra, and  a cornercorner with one P(7)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 40-55°. In the third P site, P(3) is bonded to one O(12), one O(2), one O(3), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Na(6)O6 octahedra,  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one Co(3)O6 octahedra, and  a cornercorner with one P(8)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 45-53°. In the fourth P site, P(4) is bonded to one O(13), one O(14), one O(27), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Co(3)O6 octahedra,  a cornercorner with one Co(4)O6 octahedra, corners with two equivalent Na(6)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and  an edgeedge with one Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-64°. In the fifth P site, P(5) is bonded to one O(11), one O(17), one O(22), and one O(25) atom to form PO4 tetrahedra that share  a cornercorner with one Co(1)O6 octahedra,  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one Co(3)O6 octahedra, and  a cornercorner with one P(6)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 40-45°. In the sixth P site, P(6) is bonded to one O(15), one O(22), one O(24), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Na(6)O6 octahedra,  a cornercorner with one Co(1)O6 octahedra,  a cornercorner with one Co(4)O6 octahedra, and  a cornercorner with one P(5)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 45-66°. In the seventh P site, P(7) is bonded to one O(10), one O(18), one O(20), and one O(21) atom to form PO4 tetrahedra that share  a cornercorner with one Co(3)O6 octahedra,  a cornercorner with one Co(4)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, and  an edgeedge with one Co(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-50°. In the eighth P site, P(8) is bonded to one O(1), one O(19), one O(23), and one O(3) atom to form PO4 tetrahedra that share  a cornercorner with one Co(1)O6 octahedra,  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one Co(4)O6 octahedra, and  a cornercorner with one P(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 41-47°. There are twenty-eight inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one Na(8), one Co(1), and one P(8) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Na(4), one Na(5), one Co(3), and one P(3) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Na(4), one P(3), and one P(8) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Na(5), one Na(8), one Co(3), and one P(1) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Na(6), one Co(3), and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Na(3), one Na(8), one Co(2), and one P(1) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Na(5), one Co(4), and one P(6) atom. In the eighth O site, O(8) is bonded to one Na(2), one Na(6), one Na(7), one Co(1), and one P(4) atom to form distorted ONa3CoP trigonal bipyramids that share corners with two equivalent O(15)Na3P tetrahedra,  an edgeedge with one O(9)Na3P tetrahedra, and  an edgeedge with one O(18)Na3CoP trigonal bipyramid. In the ninth O site, O(9) is bonded to one Na(3), one Na(6), one Na(7), and one P(3) atom to form distorted ONa3P tetrahedra that share corners with two equivalent O(18)Na3CoP trigonal bipyramids,  an edgeedge with one O(15)Na3P tetrahedra, and  an edgeedge with one O(8)Na3CoP trigonal bipyramid. In the tenth O site, O(10) is bonded in a distorted bent 150 degrees geometry to one P(2) and one P(7) atom. In the eleventh O site, O(11) is bonded in a distorted rectangular see-saw-like geometry to one Na(4), one Na(5), one Co(3), and one P(5) atom. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to one Na(1), one Na(8), one Co(2), and one P(3) atom. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to one Na(1), one Co(1), one Co(4), and one P(4) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal planar geometry to one Na(6), one Co(3), and one P(4) atom. In the fifteenth O site, O(15) is bonded to one Na(2), one Na(3), one Na(6), and one P(6) atom to form distorted ONa3P tetrahedra that share corners with two equivalent O(8)Na3CoP trigonal bipyramids,  an edgeedge with one O(9)Na3P tetrahedra, and  an edgeedge with one O(18)Na3CoP trigonal bipyramid. In the sixteenth O site, O(16) is bonded in a 4-coordinate geometry to one Na(3), one Na(4), one Co(4), and one P(2) atom. In the seventeenth O site, O(17) is bonded in a 4-coordinate geometry to one Na(1), one Na(8), one Co(2), and one P(5) atom. In the eighteenth O site, O(18) is bonded to one Na(2), one Na(3), one Na(7), one Co(2), and one P(7) atom to form distorted ONa3CoP trigonal bipyramids that share corners with two equivalent O(9)Na3P tetrahedra,  an edgeedge with one O(15)Na3P tetrahedra, and  an edgeedge with one O(8)Na3CoP trigonal bipyramid. In the nineteenth O site, O(19) is bonded in a 4-coordinate geometry to one Na(1), one Na(5), one Co(4), and one P(8) atom. In the twentieth O site, O(20) is bonded in a distorted trigonal planar geometry to one Na(3), one Co(4), and one P(7) atom. In the twenty-first O site, O(21) is bonded in a 3-coordinate geometry to one Co(2), one Co(3), and one P(7) atom. In the twenty-second O site, O(22) is bonded in a distorted trigonal planar geometry to one Na(4), one P(5), and one P(6) atom. In the twenty-third O site, O(23) is bonded in a distorted trigonal planar geometry to one Na(7), one Co(2), and one P(8) atom. In the twenty-fourth O site, O(24) is bonded in a 4-coordinate geometry to one Na(1), one Na(8), one Co(1), and one P(6) atom. In the twenty-fifth O site, O(25) is bonded in a 3-coordinate geometry to one Na(2), one Co(1), and one P(5) atom. In the twenty-sixth O site, O(26) is bonded in a distorted trigonal pyramidal geometry to one Na(1), one Na(4), one Co(4), and one P(2) atom. In the twenty-seventh O site, O(27) is bonded in a bent 120 degrees geometry to one P(1) and one P(4) atom. In the twenty-eighth O site, O(28) is bonded in a 4-coordinate geometry to one Na(1), one Na(6), one Co(1), and one P(2) atom. is represented by the CIF file [CIF]
data_Na2CoP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.546
_cell_length_b   9.553
_cell_length_c   11.069
_cell_angle_alpha   64.679
_cell_angle_beta   85.925
_cell_angle_gamma   73.428
_symmetry_Int_Tables_number   1
_cell_volume   598.689
_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  0.780  0.148  0.890  1.0
  Na  Na1  1  0.603  0.877  0.650  1.0
  Na  Na2  1  0.035  0.813  0.478  1.0
  Na  Na3  1  0.844  0.488  0.946  1.0
  Na  Na4  1  0.394  0.506  0.034  1.0
  Na  Na5  1  0.968  0.184  0.522  1.0
  Na  Na6  1  0.389  0.124  0.349  1.0
  Na  Na7  1  0.174  0.854  0.097  1.0
  Co  Co8  1  0.281  0.105  0.781  1.0
  Co  Co9  1  0.720  0.888  0.224  1.0
  Co  Co10  1  0.643  0.499  0.266  1.0
  Co  Co11  1  0.363  0.493  0.740  1.0
  P  P12  1  0.120  0.545  0.316  1.0
  P  P13  1  0.883  0.445  0.690  1.0
  P  P14  1  0.922  0.178  0.209  1.0
  P  P15  1  0.423  0.297  0.543  1.0
  P  P16  1  0.707  0.806  0.963  1.0
  P  P17  1  0.079  0.817  0.792  1.0
  P  P18  1  0.579  0.697  0.461  1.0
  P  P19  1  0.299  0.183  0.041  1.0
  O  O20  1  0.227  0.101  0.967  1.0
  O  O21  1  0.722  0.321  0.186  1.0
  O  O22  1  0.084  0.270  0.098  1.0
  O  O23  1  0.308  0.538  0.224  1.0
  O  O24  1  0.968  0.455  0.305  1.0
  O  O25  1  0.016  0.718  0.300  1.0
  O  O26  1  0.283  0.679  0.809  1.0
  O  O27  1  0.358  0.144  0.563  1.0
  O  O28  1  0.036  0.097  0.347  1.0
  O  O29  1  0.783  0.545  0.537  1.0
  O  O30  1  0.621  0.663  0.049  1.0
  O  O31  1  0.886  0.060  0.159  1.0
  O  O32  1  0.444  0.292  0.684  1.0
  O  O33  1  0.614  0.318  0.458  1.0
  O  O34  1  0.959  0.898  0.656  1.0
  O  O35  1  0.035  0.529  0.712  1.0
  O  O36  1  0.778  0.886  0.039  1.0
  O  O37  1  0.639  0.851  0.441  1.0
  O  O38  1  0.388  0.323  0.950  1.0
  O  O39  1  0.389  0.673  0.547  1.0
  O  O40  1  0.563  0.699  0.322  1.0
  O  O41  1  0.924  0.721  0.905  1.0
  O  O42  1  0.438  0.063  0.168  1.0
  O  O43  1  0.114  0.934  0.843  1.0
  O  O44  1  0.567  0.929  0.836  1.0
  O  O45  1  0.695  0.451  0.783  1.0
  O  O46  1  0.224  0.452  0.469  1.0
  O  O47  1  0.984  0.274  0.703  1.0
[/CIF]
.