The compound described by CaH2P2O7 crystallizes in the monoclinic C2/c space group. Ca(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CaO6 octahedra that share corners with six equivalent P(1)O4 tetrahedra. P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share corners with three equivalent Ca(1)O6 octahedra and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 8-52°. H(1) is bonded in a linear geometry to one O(1) and one O(2) atom. There are four inequivalent O sites. In the first O site, O(4) is bonded in a bent 120 degrees geometry to two equivalent P(1) atoms. In the second O site, O(1) is bonded in a distorted trigonal planar geometry to one Ca(1), one P(1), and one H(1) atom. In the third O site, O(2) is bonded in a distorted trigonal planar geometry to one Ca(1), one P(1), and one H(1) atom. In the fourth O site, O(3) is bonded in a linear geometry to one Ca(1) and one P(1) atom. is represented by the CIF file [CIF]
data_CaP2H2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.531
_cell_length_b   5.531
_cell_length_c   9.902
_cell_angle_alpha   82.759
_cell_angle_beta   82.759
_cell_angle_gamma   94.698
_symmetry_Int_Tables_number   1
_cell_volume   296.621
_cell_formula_units_Z   2
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  0.000  0.000  0.000  1.0
  Ca  Ca1  1  0.000  0.000  0.500  1.0
  P  P2  1  0.223  0.451  0.190  1.0
  P  P3  1  0.549  0.777  0.310  1.0
  P  P4  1  0.777  0.549  0.810  1.0
  P  P5  1  0.451  0.223  0.690  1.0
  H  H6  1  0.921  0.506  0.348  1.0
  H  H7  1  0.494  0.079  0.152  1.0
  H  H8  1  0.079  0.494  0.652  1.0
  H  H9  1  0.506  0.921  0.848  1.0
  O  O10  1  0.270  0.225  0.123  1.0
  O  O11  1  0.775  0.730  0.377  1.0
  O  O12  1  0.730  0.775  0.877  1.0
  O  O13  1  0.225  0.270  0.623  1.0
  O  O14  1  0.026  0.368  0.325  1.0
  O  O15  1  0.632  0.974  0.175  1.0
  O  O16  1  0.974  0.632  0.675  1.0
  O  O17  1  0.368  0.026  0.825  1.0
  O  O18  1  0.149  0.668  0.105  1.0
  O  O19  1  0.332  0.851  0.395  1.0
  O  O20  1  0.851  0.332  0.895  1.0
  O  O21  1  0.668  0.149  0.605  1.0
  O  O22  1  0.476  0.524  0.250  1.0
  O  O23  1  0.524  0.476  0.750  1.0
[/CIF]
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The compound described by CaH2P2O7 crystallizes in the monoclinic C2/c space group. Ca(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CaO6 octahedra that share corners with six equivalent P(1)O4 tetrahedra. P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share corners with three equivalent Ca(1)O6 octahedra and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 8-52°. H(1) is bonded in a linear geometry to one O(1) and one O(2) atom. There are four inequivalent O sites. In the first O site, O(4) is bonded in a bent 120 degrees geometry to two equivalent P(1) atoms. In the second O site, O(1) is bonded in a distorted trigonal planar geometry to one Ca(1), one P(1), and one H(1) atom. In the third O site, O(2) is bonded in a distorted trigonal planar geometry to one Ca(1), one P(1), and one H(1) atom. In the fourth O site, O(3) is bonded in a linear geometry to one Ca(1) and one P(1) atom. is represented by the CIF file [CIF]
data_CaP2H2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.531
_cell_length_b   5.531
_cell_length_c   9.902
_cell_angle_alpha   82.759
_cell_angle_beta   82.759
_cell_angle_gamma   94.698
_symmetry_Int_Tables_number   1
_cell_volume   296.621
_cell_formula_units_Z   2
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  0.000  0.000  0.000  1.0
  Ca  Ca1  1  0.000  0.000  0.500  1.0
  P  P2  1  0.223  0.451  0.190  1.0
  P  P3  1  0.549  0.777  0.310  1.0
  P  P4  1  0.777  0.549  0.810  1.0
  P  P5  1  0.451  0.223  0.690  1.0
  H  H6  1  0.921  0.506  0.348  1.0
  H  H7  1  0.494  0.079  0.152  1.0
  H  H8  1  0.079  0.494  0.652  1.0
  H  H9  1  0.506  0.921  0.848  1.0
  O  O10  1  0.270  0.225  0.123  1.0
  O  O11  1  0.775  0.730  0.377  1.0
  O  O12  1  0.730  0.775  0.877  1.0
  O  O13  1  0.225  0.270  0.623  1.0
  O  O14  1  0.026  0.368  0.325  1.0
  O  O15  1  0.632  0.974  0.175  1.0
  O  O16  1  0.974  0.632  0.675  1.0
  O  O17  1  0.368  0.026  0.825  1.0
  O  O18  1  0.149  0.668  0.105  1.0
  O  O19  1  0.332  0.851  0.395  1.0
  O  O20  1  0.851  0.332  0.895  1.0
  O  O21  1  0.668  0.149  0.605  1.0
  O  O22  1  0.476  0.524  0.250  1.0
  O  O23  1  0.524  0.476  0.750  1.0
[/CIF]
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