The crystal structure described by K2H2P2O7 crystallizes in the triclinic P-1 space group. There are four inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(13), one O(3), one O(5), and one O(8) atom. In the second K site, K(2) is bonded in a 6-coordinate geometry to one O(13), one O(3), one O(4), one O(5), and two equivalent O(10) atoms. In the third K site, K(3) is bonded in a 7-coordinate geometry to one O(11), one O(14), one O(2), one O(3), one O(9), and two equivalent O(7) atoms. In the fourth K site, K(4) is bonded in a 7-coordinate geometry to one O(11), one O(14), one O(2), one O(4), one O(6), one O(7), and one O(9) atom. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(11), one O(2), and one O(3) atom to form corner-sharing PO4 tetrahedra. In the second P site, P(2) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form corner-sharing PO4 tetrahedra. In the third P site, P(3) is bonded to one O(12), one O(6), one O(7), and one O(8) atom to form corner-sharing PO4 tetrahedra. In the fourth P site, P(4) is bonded to one O(10), one O(11), one O(12), and one O(9) atom to form corner-sharing PO4 tetrahedra. There are four inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(13) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(13) atom. In the third H site, H(3) is bonded in a single-bond geometry to one O(14) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(14) atom. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one K(1), one P(1), and one P(2) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one K(3), one K(4), and one P(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one K(1), one K(2), one K(3), and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one K(2), one K(4), and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one K(1), one K(2), and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to one K(4), one P(2), and one P(3) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one K(4), two equivalent K(3), and one P(3) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to one K(1) and one P(3) atom. In the ninth O site, O(9) is bonded in a distorted single-bond geometry to one K(3), one K(4), and one P(4) atom. In the tenth O site, O(10) is bonded in a distorted single-bond geometry to one K(1), two equivalent K(2), and one P(4) atom. In the eleventh O site, O(11) is bonded in a distorted bent 120 degrees geometry to one K(3), one K(4), one P(1), and one P(4) atom. In the twelfth O site, O(12) is bonded in a bent 120 degrees geometry to one P(3) and one P(4) atom. In the thirteenth O site, O(13) is bonded in a distorted water-like geometry to one K(1), one K(2), one H(1), and one H(2) atom. In the fourteenth O site, O(14) is bonded in a distorted water-like geometry to one K(3), one K(4), one H(3), and one H(4) atom. is represented by the CIF card [CIF]
data_K2P2H2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.246
_cell_length_b   8.316
_cell_length_c   11.285
_cell_angle_alpha   82.785
_cell_angle_beta   84.646
_cell_angle_gamma   88.900
_symmetry_Int_Tables_number   1
_cell_volume   764.345
_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  0.246  0.706  0.948  1.0
  K  K1  1  0.754  0.294  0.052  1.0
  K  K2  1  0.713  0.881  0.925  1.0
  K  K3  1  0.287  0.119  0.075  1.0
  K  K4  1  0.609  0.701  0.571  1.0
  K  K5  1  0.391  0.299  0.429  1.0
  K  K6  1  0.820  0.222  0.549  1.0
  K  K7  1  0.180  0.778  0.451  1.0
  P  P8  1  0.372  0.996  0.704  1.0
  P  P9  1  0.628  0.004  0.296  1.0
  P  P10  1  0.058  0.139  0.802  1.0
  P  P11  1  0.942  0.861  0.198  1.0
  P  P12  1  0.214  0.455  0.714  1.0
  P  P13  1  0.786  0.545  0.286  1.0
  P  P14  1  0.518  0.287  0.783  1.0
  P  P15  1  0.482  0.713  0.217  1.0
  H  H16  1  0.725  0.522  0.827  1.0
  H  H17  1  0.275  0.478  0.173  1.0
  H  H18  1  0.897  0.556  0.862  1.0
  H  H19  1  0.103  0.444  0.138  1.0
  H  H20  1  0.938  0.881  0.657  1.0
  H  H21  1  0.062  0.119  0.343  1.0
  H  H22  1  0.972  0.700  0.676  1.0
  H  H23  1  0.028  0.300  0.324  1.0
  O  O24  1  0.226  0.030  0.807  1.0
  O  O25  1  0.774  0.970  0.193  1.0
  O  O26  1  0.311  0.983  0.585  1.0
  O  O27  1  0.689  0.017  0.415  1.0
  O  O28  1  0.473  0.862  0.763  1.0
  O  O29  1  0.527  0.138  0.237  1.0
  O  O30  1  0.933  0.049  0.747  1.0
  O  O31  1  0.067  0.951  0.253  1.0
  O  O32  1  0.021  0.189  0.924  1.0
  O  O33  1  0.979  0.811  0.076  1.0
  O  O34  1  0.113  0.292  0.701  1.0
  O  O35  1  0.887  0.708  0.299  1.0
  O  O36  1  0.296  0.513  0.593  1.0
  O  O37  1  0.704  0.487  0.407  1.0
  O  O38  1  0.103  0.570  0.778  1.0
  O  O39  1  0.897  0.430  0.222  1.0
  O  O40  1  0.644  0.403  0.719  1.0
  O  O41  1  0.356  0.597  0.281  1.0
  O  O42  1  0.549  0.191  0.900  1.0
  O  O43  1  0.451  0.809  0.100  1.0
  O  O44  1  0.475  0.168  0.685  1.0
  O  O45  1  0.525  0.832  0.315  1.0
  O  O46  1  0.346  0.386  0.807  1.0
  O  O47  1  0.654  0.614  0.193  1.0
  O  O48  1  0.781  0.567  0.889  1.0
  O  O49  1  0.219  0.433  0.111  1.0
  O  O50  1  0.919  0.782  0.621  1.0
  O  O51  1  0.081  0.218  0.379  1.0
[/CIF]
.
The crystal structure described by K2H2P2O7 crystallizes in the triclinic P-1 space group. There are four inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(13), one O(3), one O(5), and one O(8) atom. In the second K site, K(2) is bonded in a 6-coordinate geometry to one O(13), one O(3), one O(4), one O(5), and two equivalent O(10) atoms. In the third K site, K(3) is bonded in a 7-coordinate geometry to one O(11), one O(14), one O(2), one O(3), one O(9), and two equivalent O(7) atoms. In the fourth K site, K(4) is bonded in a 7-coordinate geometry to one O(11), one O(14), one O(2), one O(4), one O(6), one O(7), and one O(9) atom. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(11), one O(2), and one O(3) atom to form corner-sharing PO4 tetrahedra. In the second P site, P(2) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form corner-sharing PO4 tetrahedra. In the third P site, P(3) is bonded to one O(12), one O(6), one O(7), and one O(8) atom to form corner-sharing PO4 tetrahedra. In the fourth P site, P(4) is bonded to one O(10), one O(11), one O(12), and one O(9) atom to form corner-sharing PO4 tetrahedra. There are four inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(13) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(13) atom. In the third H site, H(3) is bonded in a single-bond geometry to one O(14) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(14) atom. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one K(1), one P(1), and one P(2) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one K(3), one K(4), and one P(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one K(1), one K(2), one K(3), and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one K(2), one K(4), and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one K(1), one K(2), and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to one K(4), one P(2), and one P(3) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one K(4), two equivalent K(3), and one P(3) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to one K(1) and one P(3) atom. In the ninth O site, O(9) is bonded in a distorted single-bond geometry to one K(3), one K(4), and one P(4) atom. In the tenth O site, O(10) is bonded in a distorted single-bond geometry to one K(1), two equivalent K(2), and one P(4) atom. In the eleventh O site, O(11) is bonded in a distorted bent 120 degrees geometry to one K(3), one K(4), one P(1), and one P(4) atom. In the twelfth O site, O(12) is bonded in a bent 120 degrees geometry to one P(3) and one P(4) atom. In the thirteenth O site, O(13) is bonded in a distorted water-like geometry to one K(1), one K(2), one H(1), and one H(2) atom. In the fourteenth O site, O(14) is bonded in a distorted water-like geometry to one K(3), one K(4), one H(3), and one H(4) atom. is represented by the CIF card [CIF]
data_K2P2H2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.246
_cell_length_b   8.316
_cell_length_c   11.285
_cell_angle_alpha   82.785
_cell_angle_beta   84.646
_cell_angle_gamma   88.900
_symmetry_Int_Tables_number   1
_cell_volume   764.345
_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  0.246  0.706  0.948  1.0
  K  K1  1  0.754  0.294  0.052  1.0
  K  K2  1  0.713  0.881  0.925  1.0
  K  K3  1  0.287  0.119  0.075  1.0
  K  K4  1  0.609  0.701  0.571  1.0
  K  K5  1  0.391  0.299  0.429  1.0
  K  K6  1  0.820  0.222  0.549  1.0
  K  K7  1  0.180  0.778  0.451  1.0
  P  P8  1  0.372  0.996  0.704  1.0
  P  P9  1  0.628  0.004  0.296  1.0
  P  P10  1  0.058  0.139  0.802  1.0
  P  P11  1  0.942  0.861  0.198  1.0
  P  P12  1  0.214  0.455  0.714  1.0
  P  P13  1  0.786  0.545  0.286  1.0
  P  P14  1  0.518  0.287  0.783  1.0
  P  P15  1  0.482  0.713  0.217  1.0
  H  H16  1  0.725  0.522  0.827  1.0
  H  H17  1  0.275  0.478  0.173  1.0
  H  H18  1  0.897  0.556  0.862  1.0
  H  H19  1  0.103  0.444  0.138  1.0
  H  H20  1  0.938  0.881  0.657  1.0
  H  H21  1  0.062  0.119  0.343  1.0
  H  H22  1  0.972  0.700  0.676  1.0
  H  H23  1  0.028  0.300  0.324  1.0
  O  O24  1  0.226  0.030  0.807  1.0
  O  O25  1  0.774  0.970  0.193  1.0
  O  O26  1  0.311  0.983  0.585  1.0
  O  O27  1  0.689  0.017  0.415  1.0
  O  O28  1  0.473  0.862  0.763  1.0
  O  O29  1  0.527  0.138  0.237  1.0
  O  O30  1  0.933  0.049  0.747  1.0
  O  O31  1  0.067  0.951  0.253  1.0
  O  O32  1  0.021  0.189  0.924  1.0
  O  O33  1  0.979  0.811  0.076  1.0
  O  O34  1  0.113  0.292  0.701  1.0
  O  O35  1  0.887  0.708  0.299  1.0
  O  O36  1  0.296  0.513  0.593  1.0
  O  O37  1  0.704  0.487  0.407  1.0
  O  O38  1  0.103  0.570  0.778  1.0
  O  O39  1  0.897  0.430  0.222  1.0
  O  O40  1  0.644  0.403  0.719  1.0
  O  O41  1  0.356  0.597  0.281  1.0
  O  O42  1  0.549  0.191  0.900  1.0
  O  O43  1  0.451  0.809  0.100  1.0
  O  O44  1  0.475  0.168  0.685  1.0
  O  O45  1  0.525  0.832  0.315  1.0
  O  O46  1  0.346  0.386  0.807  1.0
  O  O47  1  0.654  0.614  0.193  1.0
  O  O48  1  0.781  0.567  0.889  1.0
  O  O49  1  0.219  0.433  0.111  1.0
  O  O50  1  0.919  0.782  0.621  1.0
  O  O51  1  0.081  0.218  0.379  1.0
[/CIF]
.