The compound described by K2MnP2O7 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(1), one O(2), one O(3), one O(7), two equivalent O(6), and three equivalent O(5) atoms. In the second K site, K(2) is bonded in a 9-coordinate geometry to one O(3), one O(7), two equivalent O(1), two equivalent O(2), and three equivalent O(4) atoms. Mn(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(7) atom to form MnO6 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(1), one O(2), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with three equivalent Mn(1)O6 octahedra and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 6-46°. In the second P site, P(2) is bonded to one O(3), one O(4), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Mn(1)O6 octahedra and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 14-41°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one K(1), two equivalent K(2), one Mn(1), and one P(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one K(1), two equivalent K(2), one Mn(1), and one P(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one K(1), one K(2), one Mn(1), and one P(2) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to three equivalent K(2), one Mn(1), and one P(2) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to three equivalent K(1), one Mn(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to two equivalent K(1), one P(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to one K(1), one K(2), one Mn(1), and one P(2) atom. is represented by the CIF file [CIF]
data_K2MnP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.604
_cell_length_b   9.698
_cell_length_c   14.050
_cell_angle_alpha   62.528
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   677.445
_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  0.267  0.491  0.139  1.0
  K  K1  1  0.233  0.491  0.639  1.0
  K  K2  1  0.727  0.965  0.677  1.0
  K  K3  1  0.733  0.509  0.861  1.0
  K  K4  1  0.273  0.035  0.323  1.0
  K  K5  1  0.767  0.509  0.361  1.0
  K  K6  1  0.773  0.965  0.177  1.0
  K  K7  1  0.227  0.035  0.823  1.0
  Mn  Mn8  1  0.242  0.233  0.018  1.0
  Mn  Mn9  1  0.742  0.767  0.482  1.0
  Mn  Mn10  1  0.258  0.233  0.518  1.0
  Mn  Mn11  1  0.758  0.767  0.982  1.0
  P  P12  1  0.259  0.669  0.362  1.0
  P  P13  1  0.241  0.669  0.862  1.0
  P  P14  1  0.225  0.827  0.621  1.0
  P  P15  1  0.759  0.331  0.138  1.0
  P  P16  1  0.775  0.173  0.379  1.0
  P  P17  1  0.275  0.827  0.121  1.0
  P  P18  1  0.725  0.173  0.879  1.0
  P  P19  1  0.741  0.331  0.638  1.0
  O  O20  1  0.045  0.744  0.388  1.0
  O  O21  1  0.497  0.751  0.356  1.0
  O  O22  1  0.955  0.256  0.612  1.0
  O  O23  1  0.027  0.219  0.397  1.0
  O  O24  1  0.973  0.781  0.603  1.0
  O  O25  1  0.732  0.020  0.872  1.0
  O  O26  1  0.229  0.492  0.930  1.0
  O  O27  1  0.268  0.980  0.128  1.0
  O  O28  1  0.003  0.751  0.856  1.0
  O  O29  1  0.200  0.688  0.241  1.0
  O  O30  1  0.914  0.191  0.951  1.0
  O  O31  1  0.768  0.020  0.372  1.0
  O  O32  1  0.503  0.249  0.644  1.0
  O  O33  1  0.232  0.980  0.628  1.0
  O  O34  1  0.300  0.688  0.741  1.0
  O  O35  1  0.800  0.312  0.759  1.0
  O  O36  1  0.271  0.492  0.430  1.0
  O  O37  1  0.545  0.256  0.112  1.0
  O  O38  1  0.771  0.508  0.070  1.0
  O  O39  1  0.729  0.508  0.570  1.0
  O  O40  1  0.997  0.249  0.144  1.0
  O  O41  1  0.700  0.312  0.259  1.0
  O  O42  1  0.586  0.191  0.451  1.0
  O  O43  1  0.473  0.219  0.897  1.0
  O  O44  1  0.414  0.809  0.549  1.0
  O  O45  1  0.527  0.781  0.103  1.0
  O  O46  1  0.455  0.744  0.888  1.0
  O  O47  1  0.086  0.809  0.049  1.0
[/CIF]
.
The compound described by K2MnP2O7 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(1), one O(2), one O(3), one O(7), two equivalent O(6), and three equivalent O(5) atoms. In the second K site, K(2) is bonded in a 9-coordinate geometry to one O(3), one O(7), two equivalent O(1), two equivalent O(2), and three equivalent O(4) atoms. Mn(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(7) atom to form MnO6 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(1), one O(2), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with three equivalent Mn(1)O6 octahedra and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 6-46°. In the second P site, P(2) is bonded to one O(3), one O(4), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Mn(1)O6 octahedra and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 14-41°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one K(1), two equivalent K(2), one Mn(1), and one P(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one K(1), two equivalent K(2), one Mn(1), and one P(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one K(1), one K(2), one Mn(1), and one P(2) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to three equivalent K(2), one Mn(1), and one P(2) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to three equivalent K(1), one Mn(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to two equivalent K(1), one P(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to one K(1), one K(2), one Mn(1), and one P(2) atom. is represented by the CIF file [CIF]
data_K2MnP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.604
_cell_length_b   9.698
_cell_length_c   14.050
_cell_angle_alpha   62.528
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   677.445
_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  0.267  0.491  0.139  1.0
  K  K1  1  0.233  0.491  0.639  1.0
  K  K2  1  0.727  0.965  0.677  1.0
  K  K3  1  0.733  0.509  0.861  1.0
  K  K4  1  0.273  0.035  0.323  1.0
  K  K5  1  0.767  0.509  0.361  1.0
  K  K6  1  0.773  0.965  0.177  1.0
  K  K7  1  0.227  0.035  0.823  1.0
  Mn  Mn8  1  0.242  0.233  0.018  1.0
  Mn  Mn9  1  0.742  0.767  0.482  1.0
  Mn  Mn10  1  0.258  0.233  0.518  1.0
  Mn  Mn11  1  0.758  0.767  0.982  1.0
  P  P12  1  0.259  0.669  0.362  1.0
  P  P13  1  0.241  0.669  0.862  1.0
  P  P14  1  0.225  0.827  0.621  1.0
  P  P15  1  0.759  0.331  0.138  1.0
  P  P16  1  0.775  0.173  0.379  1.0
  P  P17  1  0.275  0.827  0.121  1.0
  P  P18  1  0.725  0.173  0.879  1.0
  P  P19  1  0.741  0.331  0.638  1.0
  O  O20  1  0.045  0.744  0.388  1.0
  O  O21  1  0.497  0.751  0.356  1.0
  O  O22  1  0.955  0.256  0.612  1.0
  O  O23  1  0.027  0.219  0.397  1.0
  O  O24  1  0.973  0.781  0.603  1.0
  O  O25  1  0.732  0.020  0.872  1.0
  O  O26  1  0.229  0.492  0.930  1.0
  O  O27  1  0.268  0.980  0.128  1.0
  O  O28  1  0.003  0.751  0.856  1.0
  O  O29  1  0.200  0.688  0.241  1.0
  O  O30  1  0.914  0.191  0.951  1.0
  O  O31  1  0.768  0.020  0.372  1.0
  O  O32  1  0.503  0.249  0.644  1.0
  O  O33  1  0.232  0.980  0.628  1.0
  O  O34  1  0.300  0.688  0.741  1.0
  O  O35  1  0.800  0.312  0.759  1.0
  O  O36  1  0.271  0.492  0.430  1.0
  O  O37  1  0.545  0.256  0.112  1.0
  O  O38  1  0.771  0.508  0.070  1.0
  O  O39  1  0.729  0.508  0.570  1.0
  O  O40  1  0.997  0.249  0.144  1.0
  O  O41  1  0.700  0.312  0.259  1.0
  O  O42  1  0.586  0.191  0.451  1.0
  O  O43  1  0.473  0.219  0.897  1.0
  O  O44  1  0.414  0.809  0.549  1.0
  O  O45  1  0.527  0.781  0.103  1.0
  O  O46  1  0.455  0.744  0.888  1.0
  O  O47  1  0.086  0.809  0.049  1.0
[/CIF]
.