The structure described by CaCr2(P2O7)2 crystallizes in the triclinic P1 space group. Ca(1) is bonded in a 8-coordinate geometry to one O(1), one O(10), one O(13), one O(3), one O(6), one O(7), one O(8), and one O(9) atom. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(12), one O(2), one O(3), one O(5), and one O(9) atom to form CrO5 square pyramids that share  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, and corners with two equivalent P(1)O4 tetrahedra. In the second Cr site, Cr(2) is bonded to one O(1), one O(10), one O(13), one O(4), and one O(6) atom to form CrO5 trigonal bipyramids that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(14), one O(3), and one O(5) atom to form PO4 tetrahedra that share corners with two equivalent Cr(1)O5 square pyramids,  a cornercorner with one P(4)O4 tetrahedra, and  a cornercorner with one Cr(2)O5 trigonal bipyramid. In the second P site, P(2) is bonded to one O(11), one O(2), one O(4), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(1)O5 square pyramid,  a cornercorner with one P(3)O4 tetrahedra, and corners with two equivalent Cr(2)O5 trigonal bipyramids. In the third P site, P(3) is bonded to one O(11), one O(13), one O(8), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(1)O5 square pyramid,  a cornercorner with one P(2)O4 tetrahedra, and  a cornercorner with one Cr(2)O5 trigonal bipyramid. In the fourth P site, P(4) is bonded to one O(10), one O(12), one O(14), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(1)O5 square pyramid,  a cornercorner with one P(1)O4 tetrahedra, and  a cornercorner with one Cr(2)O5 trigonal bipyramid. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ca(1), one Cr(2), and one P(1) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Cr(1) and one P(2) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Ca(1), one Cr(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Cr(2) and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Cr(1) and one P(1) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one Ca(1), one Cr(2), and one P(2) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Ca(1) and one P(4) atom. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one Ca(1) and one P(3) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Ca(1), one Cr(1), and one P(3) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Ca(1), one Cr(2), and one P(4) atom. In the eleventh O site, O(11) is bonded in a bent 150 degrees geometry to one P(2) and one P(3) atom. In the twelfth O site, O(12) is bonded in a distorted bent 120 degrees geometry to one Cr(1) and one P(4) atom. In the thirteenth O site, O(13) is bonded in a distorted trigonal non-coplanar geometry to one Ca(1), one Cr(2), and one P(3) atom. In the fourteenth O site, O(14) is bonded in a bent 150 degrees geometry to one P(1) and one P(4) atom. is represented by the CIF file [CIF]
data_CaCr2(P2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.350
_cell_length_b   6.434
_cell_length_c   7.124
_cell_angle_alpha   96.389
_cell_angle_beta   89.146
_cell_angle_gamma   111.727
_symmetry_Int_Tables_number   1
_cell_volume   268.557
_cell_formula_units_Z   1
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  0.694  0.715  0.379  1.0
  Cr  Cr1  1  0.742  0.130  0.800  1.0
  Cr  Cr2  1  0.254  0.874  0.199  1.0
  P  P3  1  0.849  0.665  0.881  1.0
  P  P4  1  0.154  0.335  0.115  1.0
  P  P5  1  0.747  0.215  0.383  1.0
  P  P6  1  0.258  0.790  0.617  1.0
  O  O7  1  0.939  0.749  0.089  1.0
  O  O8  1  0.048  0.256  0.917  1.0
  O  O9  1  0.743  0.816  0.804  1.0
  O  O10  1  0.266  0.183  0.182  1.0
  O  O11  1  0.694  0.417  0.869  1.0
  O  O12  1  0.316  0.585  0.139  1.0
  O  O13  1  0.369  0.632  0.542  1.0
  O  O14  1  0.645  0.380  0.455  1.0
  O  O15  1  0.846  0.123  0.539  1.0
  O  O16  1  0.126  0.842  0.452  1.0
  O  O17  1  0.950  0.337  0.253  1.0
  O  O18  1  0.412  0.004  0.738  1.0
  O  O19  1  0.588  0.002  0.257  1.0
  O  O20  1  0.062  0.665  0.756  1.0
[/CIF]
.
The structure described by CaCr2(P2O7)2 crystallizes in the triclinic P1 space group. Ca(1) is bonded in a 8-coordinate geometry to one O(1), one O(10), one O(13), one O(3), one O(6), one O(7), one O(8), and one O(9) atom. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(12), one O(2), one O(3), one O(5), and one O(9) atom to form CrO5 square pyramids that share  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, and corners with two equivalent P(1)O4 tetrahedra. In the second Cr site, Cr(2) is bonded to one O(1), one O(10), one O(13), one O(4), and one O(6) atom to form CrO5 trigonal bipyramids that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(14), one O(3), and one O(5) atom to form PO4 tetrahedra that share corners with two equivalent Cr(1)O5 square pyramids,  a cornercorner with one P(4)O4 tetrahedra, and  a cornercorner with one Cr(2)O5 trigonal bipyramid. In the second P site, P(2) is bonded to one O(11), one O(2), one O(4), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(1)O5 square pyramid,  a cornercorner with one P(3)O4 tetrahedra, and corners with two equivalent Cr(2)O5 trigonal bipyramids. In the third P site, P(3) is bonded to one O(11), one O(13), one O(8), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(1)O5 square pyramid,  a cornercorner with one P(2)O4 tetrahedra, and  a cornercorner with one Cr(2)O5 trigonal bipyramid. In the fourth P site, P(4) is bonded to one O(10), one O(12), one O(14), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(1)O5 square pyramid,  a cornercorner with one P(1)O4 tetrahedra, and  a cornercorner with one Cr(2)O5 trigonal bipyramid. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ca(1), one Cr(2), and one P(1) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Cr(1) and one P(2) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Ca(1), one Cr(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Cr(2) and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Cr(1) and one P(1) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one Ca(1), one Cr(2), and one P(2) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Ca(1) and one P(4) atom. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one Ca(1) and one P(3) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Ca(1), one Cr(1), and one P(3) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Ca(1), one Cr(2), and one P(4) atom. In the eleventh O site, O(11) is bonded in a bent 150 degrees geometry to one P(2) and one P(3) atom. In the twelfth O site, O(12) is bonded in a distorted bent 120 degrees geometry to one Cr(1) and one P(4) atom. In the thirteenth O site, O(13) is bonded in a distorted trigonal non-coplanar geometry to one Ca(1), one Cr(2), and one P(3) atom. In the fourteenth O site, O(14) is bonded in a bent 150 degrees geometry to one P(1) and one P(4) atom. is represented by the CIF file [CIF]
data_CaCr2(P2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.350
_cell_length_b   6.434
_cell_length_c   7.124
_cell_angle_alpha   96.389
_cell_angle_beta   89.146
_cell_angle_gamma   111.727
_symmetry_Int_Tables_number   1
_cell_volume   268.557
_cell_formula_units_Z   1
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  0.694  0.715  0.379  1.0
  Cr  Cr1  1  0.742  0.130  0.800  1.0
  Cr  Cr2  1  0.254  0.874  0.199  1.0
  P  P3  1  0.849  0.665  0.881  1.0
  P  P4  1  0.154  0.335  0.115  1.0
  P  P5  1  0.747  0.215  0.383  1.0
  P  P6  1  0.258  0.790  0.617  1.0
  O  O7  1  0.939  0.749  0.089  1.0
  O  O8  1  0.048  0.256  0.917  1.0
  O  O9  1  0.743  0.816  0.804  1.0
  O  O10  1  0.266  0.183  0.182  1.0
  O  O11  1  0.694  0.417  0.869  1.0
  O  O12  1  0.316  0.585  0.139  1.0
  O  O13  1  0.369  0.632  0.542  1.0
  O  O14  1  0.645  0.380  0.455  1.0
  O  O15  1  0.846  0.123  0.539  1.0
  O  O16  1  0.126  0.842  0.452  1.0
  O  O17  1  0.950  0.337  0.253  1.0
  O  O18  1  0.412  0.004  0.738  1.0
  O  O19  1  0.588  0.002  0.257  1.0
  O  O20  1  0.062  0.665  0.756  1.0
[/CIF]
.