The structure described by Ca2P2O7 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(4), two equivalent O(6), and two equivalent O(7) atoms. In the second Ca site, Ca(2) is bonded in a 8-coordinate geometry to one O(1), one O(4), one O(6), one O(7), two equivalent O(2), and two equivalent O(3) atoms. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(3), and one O(5) atom to form corner-sharing PO4 tetrahedra. In the second P site, P(2) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form corner-sharing PO4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the second O site, O(6) is bonded in a 4-coordinate geometry to one Ca(2), two equivalent Ca(1), and one P(2) atom. In the third O site, O(7) is bonded in a 4-coordinate geometry to one Ca(2), two equivalent Ca(1), and one P(2) atom. In the fourth O site, O(1) is bonded in a 3-coordinate geometry to one Ca(1), one Ca(2), and one P(1) atom. In the fifth O site, O(2) is bonded in a 1-coordinate geometry to one Ca(1), two equivalent Ca(2), and one P(1) atom. In the sixth O site, O(3) is bonded in a 4-coordinate geometry to one Ca(1), two equivalent Ca(2), and one P(1) atom. In the seventh O site, O(4) is bonded in a 3-coordinate geometry to one Ca(1), one Ca(2), and one P(2) atom. is represented by the CIF card [CIF]
data_Ca2P2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.495
_cell_length_b   5.324
_cell_length_c   13.735
_cell_angle_alpha   67.044
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   572.048
_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
  Ca  Ca0  1  0.387  0.827  0.410  1.0
  Ca  Ca1  1  0.887  0.173  0.090  1.0
  Ca  Ca2  1  0.613  0.173  0.590  1.0
  Ca  Ca3  1  0.113  0.827  0.910  1.0
  Ca  Ca4  1  0.187  0.508  0.235  1.0
  Ca  Ca5  1  0.687  0.492  0.265  1.0
  Ca  Ca6  1  0.813  0.492  0.765  1.0
  Ca  Ca7  1  0.313  0.508  0.735  1.0
  P  P8  1  0.512  0.954  0.819  1.0
  P  P9  1  0.012  0.046  0.681  1.0
  P  P10  1  0.488  0.046  0.181  1.0
  P  P11  1  0.988  0.954  0.319  1.0
  P  P12  1  0.765  0.759  0.973  1.0
  P  P13  1  0.265  0.241  0.527  1.0
  P  P14  1  0.235  0.241  0.027  1.0
  P  P15  1  0.735  0.759  0.473  1.0
  O  O16  1  0.344  0.011  0.837  1.0
  O  O17  1  0.844  0.989  0.663  1.0
  O  O18  1  0.656  0.989  0.163  1.0
  O  O19  1  0.156  0.011  0.337  1.0
  O  O20  1  0.598  0.221  0.763  1.0
  O  O21  1  0.098  0.779  0.737  1.0
  O  O22  1  0.402  0.779  0.237  1.0
  O  O23  1  0.902  0.221  0.263  1.0
  O  O24  1  0.533  0.770  0.758  1.0
  O  O25  1  0.033  0.230  0.742  1.0
  O  O26  1  0.467  0.230  0.242  1.0
  O  O27  1  0.967  0.770  0.258  1.0
  O  O28  1  0.760  0.582  0.089  1.0
  O  O29  1  0.260  0.418  0.411  1.0
  O  O30  1  0.240  0.418  0.911  1.0
  O  O31  1  0.740  0.582  0.589  1.0
  O  O32  1  0.914  0.799  0.434  1.0
  O  O33  1  0.414  0.201  0.066  1.0
  O  O34  1  0.086  0.201  0.566  1.0
  O  O35  1  0.586  0.799  0.934  1.0
  O  O36  1  0.659  0.036  0.446  1.0
  O  O37  1  0.159  0.964  0.054  1.0
  O  O38  1  0.341  0.964  0.554  1.0
  O  O39  1  0.841  0.036  0.946  1.0
  O  O40  1  0.646  0.604  0.416  1.0
  O  O41  1  0.146  0.396  0.084  1.0
  O  O42  1  0.354  0.396  0.584  1.0
  O  O43  1  0.854  0.604  0.916  1.0
[/CIF]
.
The structure described by Ca2P2O7 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(4), two equivalent O(6), and two equivalent O(7) atoms. In the second Ca site, Ca(2) is bonded in a 8-coordinate geometry to one O(1), one O(4), one O(6), one O(7), two equivalent O(2), and two equivalent O(3) atoms. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(3), and one O(5) atom to form corner-sharing PO4 tetrahedra. In the second P site, P(2) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form corner-sharing PO4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the second O site, O(6) is bonded in a 4-coordinate geometry to one Ca(2), two equivalent Ca(1), and one P(2) atom. In the third O site, O(7) is bonded in a 4-coordinate geometry to one Ca(2), two equivalent Ca(1), and one P(2) atom. In the fourth O site, O(1) is bonded in a 3-coordinate geometry to one Ca(1), one Ca(2), and one P(1) atom. In the fifth O site, O(2) is bonded in a 1-coordinate geometry to one Ca(1), two equivalent Ca(2), and one P(1) atom. In the sixth O site, O(3) is bonded in a 4-coordinate geometry to one Ca(1), two equivalent Ca(2), and one P(1) atom. In the seventh O site, O(4) is bonded in a 3-coordinate geometry to one Ca(1), one Ca(2), and one P(2) atom. is represented by the CIF card [CIF]
data_Ca2P2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.495
_cell_length_b   5.324
_cell_length_c   13.735
_cell_angle_alpha   67.044
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   572.048
_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
  Ca  Ca0  1  0.387  0.827  0.410  1.0
  Ca  Ca1  1  0.887  0.173  0.090  1.0
  Ca  Ca2  1  0.613  0.173  0.590  1.0
  Ca  Ca3  1  0.113  0.827  0.910  1.0
  Ca  Ca4  1  0.187  0.508  0.235  1.0
  Ca  Ca5  1  0.687  0.492  0.265  1.0
  Ca  Ca6  1  0.813  0.492  0.765  1.0
  Ca  Ca7  1  0.313  0.508  0.735  1.0
  P  P8  1  0.512  0.954  0.819  1.0
  P  P9  1  0.012  0.046  0.681  1.0
  P  P10  1  0.488  0.046  0.181  1.0
  P  P11  1  0.988  0.954  0.319  1.0
  P  P12  1  0.765  0.759  0.973  1.0
  P  P13  1  0.265  0.241  0.527  1.0
  P  P14  1  0.235  0.241  0.027  1.0
  P  P15  1  0.735  0.759  0.473  1.0
  O  O16  1  0.344  0.011  0.837  1.0
  O  O17  1  0.844  0.989  0.663  1.0
  O  O18  1  0.656  0.989  0.163  1.0
  O  O19  1  0.156  0.011  0.337  1.0
  O  O20  1  0.598  0.221  0.763  1.0
  O  O21  1  0.098  0.779  0.737  1.0
  O  O22  1  0.402  0.779  0.237  1.0
  O  O23  1  0.902  0.221  0.263  1.0
  O  O24  1  0.533  0.770  0.758  1.0
  O  O25  1  0.033  0.230  0.742  1.0
  O  O26  1  0.467  0.230  0.242  1.0
  O  O27  1  0.967  0.770  0.258  1.0
  O  O28  1  0.760  0.582  0.089  1.0
  O  O29  1  0.260  0.418  0.411  1.0
  O  O30  1  0.240  0.418  0.911  1.0
  O  O31  1  0.740  0.582  0.589  1.0
  O  O32  1  0.914  0.799  0.434  1.0
  O  O33  1  0.414  0.201  0.066  1.0
  O  O34  1  0.086  0.201  0.566  1.0
  O  O35  1  0.586  0.799  0.934  1.0
  O  O36  1  0.659  0.036  0.446  1.0
  O  O37  1  0.159  0.964  0.054  1.0
  O  O38  1  0.341  0.964  0.554  1.0
  O  O39  1  0.841  0.036  0.946  1.0
  O  O40  1  0.646  0.604  0.416  1.0
  O  O41  1  0.146  0.396  0.084  1.0
  O  O42  1  0.354  0.396  0.584  1.0
  O  O43  1  0.854  0.604  0.916  1.0
[/CIF]
.