The material structure described by NbCr2Fe3(PO4)6 crystallizes in the trigonal R3 space group. Nb(1) is bonded to three equivalent O(3) and three equivalent O(6) atoms to form NbO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded in a 6-coordinate geometry to three equivalent O(2) and three equivalent O(6) atoms. In the second Cr site, Cr(2) is bonded in a 6-coordinate geometry to three equivalent O(4) and three equivalent O(7) atoms. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to three equivalent O(2) and three equivalent O(5) atoms to form distorted FeO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. In the second Fe site, Fe(2) is bonded to three equivalent O(1) and three equivalent O(4) atoms to form FeO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. In the third Fe site, Fe(3) is bonded to three equivalent O(7) and three equivalent O(8) atoms to form FeO6 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(2), one O(3), one O(4), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra, and  a cornercorner with one Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 21-51°. In the second P site, P(2) is bonded to one O(1), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra, and  a cornercorner with one Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 27-47°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Fe(2) and one P(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Cr(1), one Fe(1), and one P(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Nb(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Cr(2), one Fe(2), and one P(1) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Nb(1), one Cr(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Cr(2), one Fe(3), and one P(2) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Fe(3) and one P(1) atom. is represented by the CIF card [CIF]
data_NbCr2Fe3(PO4)6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.771
_cell_length_b   8.771
_cell_length_c   8.771
_cell_angle_alpha   59.655
_cell_angle_beta   59.655
_cell_angle_gamma   59.655
_symmetry_Int_Tables_number   1
_cell_volume   473.353
_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
  Nb  Nb0  1  0.855  0.855  0.855  1.0
  Cr  Cr1  1  0.009  0.009  0.009  1.0
  Cr  Cr2  1  0.501  0.501  0.501  1.0
  Fe  Fe3  1  0.149  0.149  0.149  1.0
  Fe  Fe4  1  0.355  0.355  0.355  1.0
  Fe  Fe5  1  0.644  0.644  0.644  1.0
  P  P6  1  0.451  0.748  0.044  1.0
  P  P7  1  0.540  0.254  0.956  1.0
  P  P8  1  0.956  0.540  0.254  1.0
  P  P9  1  0.254  0.956  0.540  1.0
  P  P10  1  0.748  0.044  0.451  1.0
  P  P11  1  0.044  0.451  0.748  1.0
  O  O12  1  0.310  0.113  0.505  1.0
  O  O13  1  0.505  0.310  0.113  1.0
  O  O14  1  0.914  0.060  0.262  1.0
  O  O15  1  0.113  0.505  0.310  1.0
  O  O16  1  0.816  0.990  0.614  1.0
  O  O17  1  0.589  0.236  0.445  1.0
  O  O18  1  0.060  0.262  0.914  1.0
  O  O19  1  0.236  0.445  0.589  1.0
  O  O20  1  0.391  0.184  0.999  1.0
  O  O21  1  0.445  0.589  0.236  1.0
  O  O22  1  0.738  0.089  0.934  1.0
  O  O23  1  0.999  0.391  0.184  1.0
  O  O24  1  0.990  0.614  0.816  1.0
  O  O25  1  0.262  0.914  0.060  1.0
  O  O26  1  0.560  0.412  0.762  1.0
  O  O27  1  0.614  0.816  0.990  1.0
  O  O28  1  0.762  0.560  0.412  1.0
  O  O29  1  0.934  0.738  0.089  1.0
  O  O30  1  0.412  0.762  0.560  1.0
  O  O31  1  0.184  0.999  0.391  1.0
  O  O32  1  0.888  0.499  0.685  1.0
  O  O33  1  0.089  0.934  0.738  1.0
  O  O34  1  0.499  0.685  0.888  1.0
  O  O35  1  0.685  0.888  0.499  1.0
[/CIF]
.
The material structure described by NbCr2Fe3(PO4)6 crystallizes in the trigonal R3 space group. Nb(1) is bonded to three equivalent O(3) and three equivalent O(6) atoms to form NbO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded in a 6-coordinate geometry to three equivalent O(2) and three equivalent O(6) atoms. In the second Cr site, Cr(2) is bonded in a 6-coordinate geometry to three equivalent O(4) and three equivalent O(7) atoms. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to three equivalent O(2) and three equivalent O(5) atoms to form distorted FeO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. In the second Fe site, Fe(2) is bonded to three equivalent O(1) and three equivalent O(4) atoms to form FeO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. In the third Fe site, Fe(3) is bonded to three equivalent O(7) and three equivalent O(8) atoms to form FeO6 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(2), one O(3), one O(4), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra, and  a cornercorner with one Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 21-51°. In the second P site, P(2) is bonded to one O(1), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra, and  a cornercorner with one Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 27-47°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Fe(2) and one P(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Cr(1), one Fe(1), and one P(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Nb(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Cr(2), one Fe(2), and one P(1) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Nb(1), one Cr(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Cr(2), one Fe(3), and one P(2) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Fe(3) and one P(1) atom. is represented by the CIF card [CIF]
data_NbCr2Fe3(PO4)6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.771
_cell_length_b   8.771
_cell_length_c   8.771
_cell_angle_alpha   59.655
_cell_angle_beta   59.655
_cell_angle_gamma   59.655
_symmetry_Int_Tables_number   1
_cell_volume   473.353
_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
  Nb  Nb0  1  0.855  0.855  0.855  1.0
  Cr  Cr1  1  0.009  0.009  0.009  1.0
  Cr  Cr2  1  0.501  0.501  0.501  1.0
  Fe  Fe3  1  0.149  0.149  0.149  1.0
  Fe  Fe4  1  0.355  0.355  0.355  1.0
  Fe  Fe5  1  0.644  0.644  0.644  1.0
  P  P6  1  0.451  0.748  0.044  1.0
  P  P7  1  0.540  0.254  0.956  1.0
  P  P8  1  0.956  0.540  0.254  1.0
  P  P9  1  0.254  0.956  0.540  1.0
  P  P10  1  0.748  0.044  0.451  1.0
  P  P11  1  0.044  0.451  0.748  1.0
  O  O12  1  0.310  0.113  0.505  1.0
  O  O13  1  0.505  0.310  0.113  1.0
  O  O14  1  0.914  0.060  0.262  1.0
  O  O15  1  0.113  0.505  0.310  1.0
  O  O16  1  0.816  0.990  0.614  1.0
  O  O17  1  0.589  0.236  0.445  1.0
  O  O18  1  0.060  0.262  0.914  1.0
  O  O19  1  0.236  0.445  0.589  1.0
  O  O20  1  0.391  0.184  0.999  1.0
  O  O21  1  0.445  0.589  0.236  1.0
  O  O22  1  0.738  0.089  0.934  1.0
  O  O23  1  0.999  0.391  0.184  1.0
  O  O24  1  0.990  0.614  0.816  1.0
  O  O25  1  0.262  0.914  0.060  1.0
  O  O26  1  0.560  0.412  0.762  1.0
  O  O27  1  0.614  0.816  0.990  1.0
  O  O28  1  0.762  0.560  0.412  1.0
  O  O29  1  0.934  0.738  0.089  1.0
  O  O30  1  0.412  0.762  0.560  1.0
  O  O31  1  0.184  0.999  0.391  1.0
  O  O32  1  0.888  0.499  0.685  1.0
  O  O33  1  0.089  0.934  0.738  1.0
  O  O34  1  0.499  0.685  0.888  1.0
  O  O35  1  0.685  0.888  0.499  1.0
[/CIF]
.