The crystal structure described by NaCrP2O7 crystallizes in the monoclinic P2_1/c space group. Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(4), one O(5), one O(6), and one O(7) atom. Cr(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form CrO6 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(7) atom to form PO4 tetrahedra that share corners with three equivalent Cr(1)O6 octahedra and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 33-54°. In the second P site, P(2) is bonded to one O(1), one O(3), one O(4), and one O(6) atom to form PO4 tetrahedra that share corners with three equivalent Cr(1)O6 octahedra and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 20-51°. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a 3-coordinate geometry to one Na(1), one Cr(1), and one P(1) atom. In the second O site, O(6) is bonded in a distorted trigonal planar geometry to one Na(1), one Cr(1), and one P(2) atom. In the third O site, O(7) is bonded in a 3-coordinate geometry to one Na(1), one Cr(1), and one P(1) atom. In the fourth O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one P(1), and one P(2) atom. In the fifth O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one Cr(1), and one P(1) atom. In the sixth O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Cr(1) and one P(2) atom. In the seventh O site, O(4) is bonded in a distorted trigonal planar geometry to one Na(1), one Cr(1), and one P(2) atom. is represented by the CIF file [CIF]
data_NaCrP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.982
_cell_length_b   7.367
_cell_length_c   9.621
_cell_angle_alpha   68.458
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   526.272
_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
  Na  Na0  1  0.478  0.709  0.296  1.0
  Na  Na1  1  0.978  0.291  0.204  1.0
  Na  Na2  1  0.522  0.291  0.704  1.0
  Na  Na3  1  0.022  0.709  0.796  1.0
  Cr  Cr4  1  0.993  0.260  0.753  1.0
  Cr  Cr5  1  0.493  0.740  0.747  1.0
  Cr  Cr6  1  0.007  0.740  0.247  1.0
  Cr  Cr7  1  0.507  0.260  0.253  1.0
  P  P8  1  0.711  0.673  0.044  1.0
  P  P9  1  0.211  0.327  0.456  1.0
  P  P10  1  0.289  0.327  0.956  1.0
  P  P11  1  0.789  0.673  0.544  1.0
  P  P12  1  0.755  0.076  0.046  1.0
  P  P13  1  0.255  0.924  0.454  1.0
  P  P14  1  0.245  0.924  0.954  1.0
  P  P15  1  0.745  0.076  0.546  1.0
  O  O16  1  0.654  0.880  0.056  1.0
  O  O17  1  0.154  0.120  0.444  1.0
  O  O18  1  0.346  0.120  0.944  1.0
  O  O19  1  0.846  0.880  0.556  1.0
  O  O20  1  0.586  0.535  0.151  1.0
  O  O21  1  0.086  0.465  0.349  1.0
  O  O22  1  0.414  0.465  0.849  1.0
  O  O23  1  0.914  0.535  0.651  1.0
  O  O24  1  0.637  0.187  0.108  1.0
  O  O25  1  0.137  0.813  0.392  1.0
  O  O26  1  0.363  0.813  0.892  1.0
  O  O27  1  0.863  0.187  0.608  1.0
  O  O28  1  0.915  0.012  0.141  1.0
  O  O29  1  0.415  0.988  0.359  1.0
  O  O30  1  0.085  0.988  0.859  1.0
  O  O31  1  0.585  0.012  0.641  1.0
  O  O32  1  0.895  0.638  0.098  1.0
  O  O33  1  0.395  0.362  0.402  1.0
  O  O34  1  0.105  0.362  0.902  1.0
  O  O35  1  0.605  0.638  0.598  1.0
  O  O36  1  0.787  0.193  0.880  1.0
  O  O37  1  0.287  0.807  0.620  1.0
  O  O38  1  0.213  0.807  0.120  1.0
  O  O39  1  0.713  0.193  0.380  1.0
  O  O40  1  0.701  0.686  0.882  1.0
  O  O41  1  0.201  0.314  0.618  1.0
  O  O42  1  0.299  0.314  0.118  1.0
  O  O43  1  0.799  0.686  0.382  1.0
[/CIF]
.
The crystal structure described by NaCrP2O7 crystallizes in the monoclinic P2_1/c space group. Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(4), one O(5), one O(6), and one O(7) atom. Cr(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form CrO6 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(7) atom to form PO4 tetrahedra that share corners with three equivalent Cr(1)O6 octahedra and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 33-54°. In the second P site, P(2) is bonded to one O(1), one O(3), one O(4), and one O(6) atom to form PO4 tetrahedra that share corners with three equivalent Cr(1)O6 octahedra and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 20-51°. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a 3-coordinate geometry to one Na(1), one Cr(1), and one P(1) atom. In the second O site, O(6) is bonded in a distorted trigonal planar geometry to one Na(1), one Cr(1), and one P(2) atom. In the third O site, O(7) is bonded in a 3-coordinate geometry to one Na(1), one Cr(1), and one P(1) atom. In the fourth O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one P(1), and one P(2) atom. In the fifth O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one Cr(1), and one P(1) atom. In the sixth O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Cr(1) and one P(2) atom. In the seventh O site, O(4) is bonded in a distorted trigonal planar geometry to one Na(1), one Cr(1), and one P(2) atom. is represented by the CIF file [CIF]
data_NaCrP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.982
_cell_length_b   7.367
_cell_length_c   9.621
_cell_angle_alpha   68.458
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   526.272
_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
  Na  Na0  1  0.478  0.709  0.296  1.0
  Na  Na1  1  0.978  0.291  0.204  1.0
  Na  Na2  1  0.522  0.291  0.704  1.0
  Na  Na3  1  0.022  0.709  0.796  1.0
  Cr  Cr4  1  0.993  0.260  0.753  1.0
  Cr  Cr5  1  0.493  0.740  0.747  1.0
  Cr  Cr6  1  0.007  0.740  0.247  1.0
  Cr  Cr7  1  0.507  0.260  0.253  1.0
  P  P8  1  0.711  0.673  0.044  1.0
  P  P9  1  0.211  0.327  0.456  1.0
  P  P10  1  0.289  0.327  0.956  1.0
  P  P11  1  0.789  0.673  0.544  1.0
  P  P12  1  0.755  0.076  0.046  1.0
  P  P13  1  0.255  0.924  0.454  1.0
  P  P14  1  0.245  0.924  0.954  1.0
  P  P15  1  0.745  0.076  0.546  1.0
  O  O16  1  0.654  0.880  0.056  1.0
  O  O17  1  0.154  0.120  0.444  1.0
  O  O18  1  0.346  0.120  0.944  1.0
  O  O19  1  0.846  0.880  0.556  1.0
  O  O20  1  0.586  0.535  0.151  1.0
  O  O21  1  0.086  0.465  0.349  1.0
  O  O22  1  0.414  0.465  0.849  1.0
  O  O23  1  0.914  0.535  0.651  1.0
  O  O24  1  0.637  0.187  0.108  1.0
  O  O25  1  0.137  0.813  0.392  1.0
  O  O26  1  0.363  0.813  0.892  1.0
  O  O27  1  0.863  0.187  0.608  1.0
  O  O28  1  0.915  0.012  0.141  1.0
  O  O29  1  0.415  0.988  0.359  1.0
  O  O30  1  0.085  0.988  0.859  1.0
  O  O31  1  0.585  0.012  0.641  1.0
  O  O32  1  0.895  0.638  0.098  1.0
  O  O33  1  0.395  0.362  0.402  1.0
  O  O34  1  0.105  0.362  0.902  1.0
  O  O35  1  0.605  0.638  0.598  1.0
  O  O36  1  0.787  0.193  0.880  1.0
  O  O37  1  0.287  0.807  0.620  1.0
  O  O38  1  0.213  0.807  0.120  1.0
  O  O39  1  0.713  0.193  0.380  1.0
  O  O40  1  0.701  0.686  0.882  1.0
  O  O41  1  0.201  0.314  0.618  1.0
  O  O42  1  0.299  0.314  0.118  1.0
  O  O43  1  0.799  0.686  0.382  1.0
[/CIF]
.