The compound described by K2SrP2O7 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 9-coordinate geometry to one O(2), one O(5), two equivalent O(1), two equivalent O(4), and three equivalent O(6) atoms. In the second K site, K(2) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(4), one O(5), two equivalent O(7), and three equivalent O(3) atoms. Sr(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form SrO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Sr(1)O6 octahedra and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 30-53°. In the second P site, P(2) is bonded to one O(1), one O(3), one O(4), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Sr(1)O6 octahedra and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 15-46°. There are seven inequivalent O sites. In the first O site, O(6) is bonded in a 1-coordinate geometry to three equivalent K(1), one Sr(1), and one P(1) atom. In the second O site, O(7) is bonded in a distorted bent 120 degrees geometry to two equivalent K(2), one P(1), and one P(2) atom. In the third O site, O(1) is bonded in a 1-coordinate geometry to one K(2), two equivalent K(1), one Sr(1), and one P(2) atom. In the fourth O site, O(2) is bonded in a 1-coordinate geometry to one K(1), one K(2), one Sr(1), and one P(1) atom. In the fifth O site, O(3) is bonded in a 1-coordinate geometry to three equivalent K(2), one Sr(1), and one P(2) atom. In the sixth O site, O(4) is bonded in a distorted single-bond geometry to one K(2), two equivalent K(1), one Sr(1), and one P(2) atom. In the seventh O site, O(5) is bonded in a 1-coordinate geometry to one K(1), one K(2), one Sr(1), and one P(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_K2SrP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.797
_cell_length_b   9.288
_cell_length_c   14.946
_cell_angle_alpha   74.158
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   774.081
_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
  K  K0  1  0.738  0.534  0.164  1.0
  K  K1  1  0.266  0.032  0.387  1.0
  K  K2  1  0.734  0.968  0.613  1.0
  K  K3  1  0.238  0.466  0.336  1.0
  K  K4  1  0.262  0.466  0.836  1.0
  K  K5  1  0.766  0.968  0.113  1.0
  K  K6  1  0.234  0.032  0.887  1.0
  K  K7  1  0.762  0.534  0.664  1.0
  Sr  Sr8  1  0.274  0.263  0.132  1.0
  Sr  Sr9  1  0.226  0.263  0.632  1.0
  Sr  Sr10  1  0.774  0.737  0.368  1.0
  Sr  Sr11  1  0.726  0.737  0.868  1.0
  P  P12  1  0.800  0.309  0.966  1.0
  P  P13  1  0.731  0.181  0.806  1.0
  P  P14  1  0.700  0.309  0.466  1.0
  P  P15  1  0.231  0.819  0.694  1.0
  P  P16  1  0.769  0.181  0.306  1.0
  P  P17  1  0.300  0.691  0.534  1.0
  P  P18  1  0.269  0.819  0.194  1.0
  P  P19  1  0.200  0.691  0.034  1.0
  O  O20  1  0.519  0.266  0.757  1.0
  O  O21  1  0.019  0.734  0.743  1.0
  O  O22  1  0.555  0.734  0.513  1.0
  O  O23  1  0.728  0.014  0.813  1.0
  O  O24  1  0.272  0.986  0.187  1.0
  O  O25  1  0.445  0.266  0.487  1.0
  O  O26  1  0.961  0.258  0.772  1.0
  O  O27  1  0.155  0.717  0.446  1.0
  O  O28  1  0.228  0.986  0.687  1.0
  O  O29  1  0.481  0.734  0.243  1.0
  O  O30  1  0.039  0.742  0.228  1.0
  O  O31  1  0.845  0.283  0.554  1.0
  O  O32  1  0.235  0.539  0.105  1.0
  O  O33  1  0.461  0.742  0.728  1.0
  O  O34  1  0.945  0.734  0.013  1.0
  O  O35  1  0.655  0.283  0.054  1.0
  O  O36  1  0.345  0.717  0.946  1.0
  O  O37  1  0.735  0.461  0.395  1.0
  O  O38  1  0.539  0.258  0.272  1.0
  O  O39  1  0.055  0.266  0.987  1.0
  O  O40  1  0.772  0.014  0.313  1.0
  O  O41  1  0.765  0.461  0.895  1.0
  O  O42  1  0.981  0.266  0.257  1.0
  O  O43  1  0.700  0.181  0.917  1.0
  O  O44  1  0.265  0.539  0.605  1.0
  O  O45  1  0.300  0.819  0.083  1.0
  O  O46  1  0.200  0.819  0.583  1.0
  O  O47  1  0.800  0.181  0.417  1.0
[/CIF]
.
The compound described by K2SrP2O7 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 9-coordinate geometry to one O(2), one O(5), two equivalent O(1), two equivalent O(4), and three equivalent O(6) atoms. In the second K site, K(2) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(4), one O(5), two equivalent O(7), and three equivalent O(3) atoms. Sr(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form SrO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Sr(1)O6 octahedra and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 30-53°. In the second P site, P(2) is bonded to one O(1), one O(3), one O(4), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Sr(1)O6 octahedra and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 15-46°. There are seven inequivalent O sites. In the first O site, O(6) is bonded in a 1-coordinate geometry to three equivalent K(1), one Sr(1), and one P(1) atom. In the second O site, O(7) is bonded in a distorted bent 120 degrees geometry to two equivalent K(2), one P(1), and one P(2) atom. In the third O site, O(1) is bonded in a 1-coordinate geometry to one K(2), two equivalent K(1), one Sr(1), and one P(2) atom. In the fourth O site, O(2) is bonded in a 1-coordinate geometry to one K(1), one K(2), one Sr(1), and one P(1) atom. In the fifth O site, O(3) is bonded in a 1-coordinate geometry to three equivalent K(2), one Sr(1), and one P(2) atom. In the sixth O site, O(4) is bonded in a distorted single-bond geometry to one K(2), two equivalent K(1), one Sr(1), and one P(2) atom. In the seventh O site, O(5) is bonded in a 1-coordinate geometry to one K(1), one K(2), one Sr(1), and one P(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_K2SrP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.797
_cell_length_b   9.288
_cell_length_c   14.946
_cell_angle_alpha   74.158
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   774.081
_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
  K  K0  1  0.738  0.534  0.164  1.0
  K  K1  1  0.266  0.032  0.387  1.0
  K  K2  1  0.734  0.968  0.613  1.0
  K  K3  1  0.238  0.466  0.336  1.0
  K  K4  1  0.262  0.466  0.836  1.0
  K  K5  1  0.766  0.968  0.113  1.0
  K  K6  1  0.234  0.032  0.887  1.0
  K  K7  1  0.762  0.534  0.664  1.0
  Sr  Sr8  1  0.274  0.263  0.132  1.0
  Sr  Sr9  1  0.226  0.263  0.632  1.0
  Sr  Sr10  1  0.774  0.737  0.368  1.0
  Sr  Sr11  1  0.726  0.737  0.868  1.0
  P  P12  1  0.800  0.309  0.966  1.0
  P  P13  1  0.731  0.181  0.806  1.0
  P  P14  1  0.700  0.309  0.466  1.0
  P  P15  1  0.231  0.819  0.694  1.0
  P  P16  1  0.769  0.181  0.306  1.0
  P  P17  1  0.300  0.691  0.534  1.0
  P  P18  1  0.269  0.819  0.194  1.0
  P  P19  1  0.200  0.691  0.034  1.0
  O  O20  1  0.519  0.266  0.757  1.0
  O  O21  1  0.019  0.734  0.743  1.0
  O  O22  1  0.555  0.734  0.513  1.0
  O  O23  1  0.728  0.014  0.813  1.0
  O  O24  1  0.272  0.986  0.187  1.0
  O  O25  1  0.445  0.266  0.487  1.0
  O  O26  1  0.961  0.258  0.772  1.0
  O  O27  1  0.155  0.717  0.446  1.0
  O  O28  1  0.228  0.986  0.687  1.0
  O  O29  1  0.481  0.734  0.243  1.0
  O  O30  1  0.039  0.742  0.228  1.0
  O  O31  1  0.845  0.283  0.554  1.0
  O  O32  1  0.235  0.539  0.105  1.0
  O  O33  1  0.461  0.742  0.728  1.0
  O  O34  1  0.945  0.734  0.013  1.0
  O  O35  1  0.655  0.283  0.054  1.0
  O  O36  1  0.345  0.717  0.946  1.0
  O  O37  1  0.735  0.461  0.395  1.0
  O  O38  1  0.539  0.258  0.272  1.0
  O  O39  1  0.055  0.266  0.987  1.0
  O  O40  1  0.772  0.014  0.313  1.0
  O  O41  1  0.765  0.461  0.895  1.0
  O  O42  1  0.981  0.266  0.257  1.0
  O  O43  1  0.700  0.181  0.917  1.0
  O  O44  1  0.265  0.539  0.605  1.0
  O  O45  1  0.300  0.819  0.083  1.0
  O  O46  1  0.200  0.819  0.583  1.0
  O  O47  1  0.800  0.181  0.417  1.0
[/CIF]
.