The material described by Na3Cr2(PO4)3 crystallizes in the monoclinic C2/c space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a distorted hexagonal planar geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. In the second Na site, Na(2) is bonded in a 8-coordinate geometry to one O(2), one O(3), one O(4), one O(5), two equivalent O(1), and two equivalent O(6) atoms. Cr(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form CrO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra and corners with four equivalent P(1)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(4), and one O(5) atom to form PO4 tetrahedra that share corners with four equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 29-36°. In the second P site, P(2) is bonded to two equivalent O(3) and two equivalent O(6) atoms to form PO4 tetrahedra that share corners with four equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 31-36°. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), two equivalent Na(2), one Cr(1), and one P(1) atom to form distorted corner-sharing ONa3CrP trigonal bipyramids. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Cr(1), and one P(1) atom. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Cr(1), and one P(2) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Na(2), one Cr(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Na(2), one Cr(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to two equivalent Na(2), one Cr(1), and one P(2) atom. is represented by the CIF card [CIF]
data_Na3Cr2(PO4)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.785
_cell_length_b   8.785
_cell_length_c   8.892
_cell_angle_alpha   60.367
_cell_angle_beta   60.367
_cell_angle_gamma   60.142
_symmetry_Int_Tables_number   1
_cell_volume   488.413
_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
  Na  Na0  1  0.500  0.000  0.500  1.0
  Na  Na1  1  0.000  0.500  0.000  1.0
  Na  Na2  1  0.748  0.885  0.751  1.0
  Na  Na3  1  0.115  0.252  0.749  1.0
  Na  Na4  1  0.252  0.115  0.249  1.0
  Na  Na5  1  0.885  0.748  0.251  1.0
  Cr  Cr6  1  0.646  0.151  0.058  1.0
  Cr  Cr7  1  0.151  0.646  0.558  1.0
  Cr  Cr8  1  0.354  0.849  0.942  1.0
  Cr  Cr9  1  0.849  0.354  0.442  1.0
  P  P10  1  0.747  0.542  0.748  1.0
  P  P11  1  0.458  0.253  0.752  1.0
  P  P12  1  0.043  0.957  0.750  1.0
  P  P13  1  0.542  0.747  0.248  1.0
  P  P14  1  0.957  0.043  0.250  1.0
  P  P15  1  0.253  0.458  0.252  1.0
  O  O16  1  0.920  0.566  0.735  1.0
  O  O17  1  0.276  0.419  0.736  1.0
  O  O18  1  0.060  0.781  0.735  1.0
  O  O19  1  0.566  0.920  0.235  1.0
  O  O20  1  0.781  0.060  0.235  1.0
  O  O21  1  0.419  0.276  0.236  1.0
  O  O22  1  0.080  0.434  0.265  1.0
  O  O23  1  0.724  0.581  0.264  1.0
  O  O24  1  0.940  0.219  0.265  1.0
  O  O25  1  0.434  0.080  0.765  1.0
  O  O26  1  0.219  0.940  0.765  1.0
  O  O27  1  0.581  0.724  0.764  1.0
  O  O28  1  0.729  0.367  0.917  1.0
  O  O29  1  0.480  0.220  0.928  1.0
  O  O30  1  0.870  0.982  0.923  1.0
  O  O31  1  0.367  0.729  0.417  1.0
  O  O32  1  0.982  0.870  0.423  1.0
  O  O33  1  0.220  0.480  0.428  1.0
  O  O34  1  0.271  0.633  0.083  1.0
  O  O35  1  0.520  0.780  0.072  1.0
  O  O36  1  0.130  0.018  0.077  1.0
  O  O37  1  0.633  0.271  0.583  1.0
  O  O38  1  0.018  0.130  0.577  1.0
  O  O39  1  0.780  0.520  0.572  1.0
[/CIF]
.
The material described by Na3Cr2(PO4)3 crystallizes in the monoclinic C2/c space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a distorted hexagonal planar geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. In the second Na site, Na(2) is bonded in a 8-coordinate geometry to one O(2), one O(3), one O(4), one O(5), two equivalent O(1), and two equivalent O(6) atoms. Cr(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form CrO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra and corners with four equivalent P(1)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(4), and one O(5) atom to form PO4 tetrahedra that share corners with four equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 29-36°. In the second P site, P(2) is bonded to two equivalent O(3) and two equivalent O(6) atoms to form PO4 tetrahedra that share corners with four equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 31-36°. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), two equivalent Na(2), one Cr(1), and one P(1) atom to form distorted corner-sharing ONa3CrP trigonal bipyramids. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Cr(1), and one P(1) atom. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Cr(1), and one P(2) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Na(2), one Cr(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Na(2), one Cr(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to two equivalent Na(2), one Cr(1), and one P(2) atom. is represented by the CIF card [CIF]
data_Na3Cr2(PO4)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.785
_cell_length_b   8.785
_cell_length_c   8.892
_cell_angle_alpha   60.367
_cell_angle_beta   60.367
_cell_angle_gamma   60.142
_symmetry_Int_Tables_number   1
_cell_volume   488.413
_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
  Na  Na0  1  0.500  0.000  0.500  1.0
  Na  Na1  1  0.000  0.500  0.000  1.0
  Na  Na2  1  0.748  0.885  0.751  1.0
  Na  Na3  1  0.115  0.252  0.749  1.0
  Na  Na4  1  0.252  0.115  0.249  1.0
  Na  Na5  1  0.885  0.748  0.251  1.0
  Cr  Cr6  1  0.646  0.151  0.058  1.0
  Cr  Cr7  1  0.151  0.646  0.558  1.0
  Cr  Cr8  1  0.354  0.849  0.942  1.0
  Cr  Cr9  1  0.849  0.354  0.442  1.0
  P  P10  1  0.747  0.542  0.748  1.0
  P  P11  1  0.458  0.253  0.752  1.0
  P  P12  1  0.043  0.957  0.750  1.0
  P  P13  1  0.542  0.747  0.248  1.0
  P  P14  1  0.957  0.043  0.250  1.0
  P  P15  1  0.253  0.458  0.252  1.0
  O  O16  1  0.920  0.566  0.735  1.0
  O  O17  1  0.276  0.419  0.736  1.0
  O  O18  1  0.060  0.781  0.735  1.0
  O  O19  1  0.566  0.920  0.235  1.0
  O  O20  1  0.781  0.060  0.235  1.0
  O  O21  1  0.419  0.276  0.236  1.0
  O  O22  1  0.080  0.434  0.265  1.0
  O  O23  1  0.724  0.581  0.264  1.0
  O  O24  1  0.940  0.219  0.265  1.0
  O  O25  1  0.434  0.080  0.765  1.0
  O  O26  1  0.219  0.940  0.765  1.0
  O  O27  1  0.581  0.724  0.764  1.0
  O  O28  1  0.729  0.367  0.917  1.0
  O  O29  1  0.480  0.220  0.928  1.0
  O  O30  1  0.870  0.982  0.923  1.0
  O  O31  1  0.367  0.729  0.417  1.0
  O  O32  1  0.982  0.870  0.423  1.0
  O  O33  1  0.220  0.480  0.428  1.0
  O  O34  1  0.271  0.633  0.083  1.0
  O  O35  1  0.520  0.780  0.072  1.0
  O  O36  1  0.130  0.018  0.077  1.0
  O  O37  1  0.633  0.271  0.583  1.0
  O  O38  1  0.018  0.130  0.577  1.0
  O  O39  1  0.780  0.520  0.572  1.0
[/CIF]
.