The compound described by MgCr2Fe3Ni(PO4)6 crystallizes in the trigonal R3 space group. Mg(1) is bonded in a 6-coordinate geometry to three equivalent O(3) and three equivalent O(8) atoms. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to three equivalent O(2) and three equivalent O(6) atoms to form distorted CrO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  a faceface with one Fe(1)O6 octahedra, and  a faceface with one Ni(1)O6 octahedra. In the second Cr site, Cr(2) is bonded to three equivalent O(4) and three equivalent O(7) atoms to form distorted CrO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  a faceface with one Fe(2)O6 octahedra, and  a faceface with one Fe(3)O6 octahedra. 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, corners with three equivalent P(2)O4 tetrahedra, and  a faceface with one Cr(1)O6 octahedra. In the second Fe site, Fe(2) is bonded to three equivalent O(1) and three equivalent O(4) atoms to form distorted FeO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and  a faceface with one Cr(2)O6 octahedra. 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, corners with three equivalent P(2)O4 tetrahedra, and  a faceface with one Cr(2)O6 octahedra. Ni(1) is bonded to three equivalent O(3) and three equivalent O(6) atoms to form NiO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and  a faceface with one Cr(1)O6 octahedra. 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 Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra, and  a cornercorner with one Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 13-54°. 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 Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra, and  a cornercorner with one Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 28-56°. 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 distorted T-shaped geometry to one Mg(1), one Ni(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 Cr(1), one Ni(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 distorted T-shaped geometry to one Mg(1), one Fe(3), and one P(1) atom. is represented by the CIF file [CIF]
data_MgCr2Fe3Ni(PO4)6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.578
_cell_length_b   8.578
_cell_length_c   8.578
_cell_angle_alpha   60.475
_cell_angle_beta   60.465
_cell_angle_gamma   60.472
_symmetry_Int_Tables_number   1
_cell_volume   451.074
_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
  Mg  Mg0  1  0.749  0.749  0.750  1.0
  Cr  Cr1  1  0.005  0.004  0.004  1.0
  Cr  Cr2  1  0.496  0.496  0.496  1.0
  Fe  Fe3  1  0.149  0.149  0.149  1.0
  Fe  Fe4  1  0.351  0.351  0.351  1.0
  Fe  Fe5  1  0.629  0.629  0.629  1.0
  Ni  Ni6  1  0.871  0.871  0.871  1.0
  P  P7  1  0.052  0.750  0.450  1.0
  P  P8  1  0.450  0.052  0.750  1.0
  P  P9  1  0.750  0.450  0.052  1.0
  P  P10  1  0.246  0.545  0.958  1.0
  P  P11  1  0.545  0.958  0.246  1.0
  P  P12  1  0.958  0.246  0.546  1.0
  O  O13  1  0.097  0.342  0.488  1.0
  O  O14  1  0.342  0.487  0.097  1.0
  O  O15  1  0.068  0.908  0.249  1.0
  O  O16  1  0.488  0.097  0.343  1.0
  O  O17  1  0.999  0.810  0.616  1.0
  O  O18  1  0.253  0.593  0.431  1.0
  O  O19  1  0.249  0.068  0.908  1.0
  O  O20  1  0.431  0.253  0.593  1.0
  O  O21  1  0.149  0.406  0.021  1.0
  O  O22  1  0.593  0.431  0.253  1.0
  O  O23  1  0.103  0.753  0.949  1.0
  O  O24  1  0.406  0.020  0.150  1.0
  O  O25  1  0.616  0.999  0.810  1.0
  O  O26  1  0.908  0.249  0.069  1.0
  O  O27  1  0.389  0.551  0.751  1.0
  O  O28  1  0.810  0.616  0.999  1.0
  O  O29  1  0.551  0.751  0.389  1.0
  O  O30  1  0.753  0.949  0.103  1.0
  O  O31  1  0.751  0.389  0.552  1.0
  O  O32  1  0.020  0.149  0.406  1.0
  O  O33  1  0.500  0.889  0.687  1.0
  O  O34  1  0.949  0.103  0.753  1.0
  O  O35  1  0.687  0.500  0.889  1.0
  O  O36  1  0.889  0.687  0.500  1.0
[/CIF]
.
The compound described by MgCr2Fe3Ni(PO4)6 crystallizes in the trigonal R3 space group. Mg(1) is bonded in a 6-coordinate geometry to three equivalent O(3) and three equivalent O(8) atoms. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to three equivalent O(2) and three equivalent O(6) atoms to form distorted CrO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  a faceface with one Fe(1)O6 octahedra, and  a faceface with one Ni(1)O6 octahedra. In the second Cr site, Cr(2) is bonded to three equivalent O(4) and three equivalent O(7) atoms to form distorted CrO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  a faceface with one Fe(2)O6 octahedra, and  a faceface with one Fe(3)O6 octahedra. 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, corners with three equivalent P(2)O4 tetrahedra, and  a faceface with one Cr(1)O6 octahedra. In the second Fe site, Fe(2) is bonded to three equivalent O(1) and three equivalent O(4) atoms to form distorted FeO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and  a faceface with one Cr(2)O6 octahedra. 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, corners with three equivalent P(2)O4 tetrahedra, and  a faceface with one Cr(2)O6 octahedra. Ni(1) is bonded to three equivalent O(3) and three equivalent O(6) atoms to form NiO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and  a faceface with one Cr(1)O6 octahedra. 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 Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra, and  a cornercorner with one Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 13-54°. 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 Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra, and  a cornercorner with one Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 28-56°. 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 distorted T-shaped geometry to one Mg(1), one Ni(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 Cr(1), one Ni(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 distorted T-shaped geometry to one Mg(1), one Fe(3), and one P(1) atom. is represented by the CIF file [CIF]
data_MgCr2Fe3Ni(PO4)6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.578
_cell_length_b   8.578
_cell_length_c   8.578
_cell_angle_alpha   60.475
_cell_angle_beta   60.465
_cell_angle_gamma   60.472
_symmetry_Int_Tables_number   1
_cell_volume   451.074
_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
  Mg  Mg0  1  0.749  0.749  0.750  1.0
  Cr  Cr1  1  0.005  0.004  0.004  1.0
  Cr  Cr2  1  0.496  0.496  0.496  1.0
  Fe  Fe3  1  0.149  0.149  0.149  1.0
  Fe  Fe4  1  0.351  0.351  0.351  1.0
  Fe  Fe5  1  0.629  0.629  0.629  1.0
  Ni  Ni6  1  0.871  0.871  0.871  1.0
  P  P7  1  0.052  0.750  0.450  1.0
  P  P8  1  0.450  0.052  0.750  1.0
  P  P9  1  0.750  0.450  0.052  1.0
  P  P10  1  0.246  0.545  0.958  1.0
  P  P11  1  0.545  0.958  0.246  1.0
  P  P12  1  0.958  0.246  0.546  1.0
  O  O13  1  0.097  0.342  0.488  1.0
  O  O14  1  0.342  0.487  0.097  1.0
  O  O15  1  0.068  0.908  0.249  1.0
  O  O16  1  0.488  0.097  0.343  1.0
  O  O17  1  0.999  0.810  0.616  1.0
  O  O18  1  0.253  0.593  0.431  1.0
  O  O19  1  0.249  0.068  0.908  1.0
  O  O20  1  0.431  0.253  0.593  1.0
  O  O21  1  0.149  0.406  0.021  1.0
  O  O22  1  0.593  0.431  0.253  1.0
  O  O23  1  0.103  0.753  0.949  1.0
  O  O24  1  0.406  0.020  0.150  1.0
  O  O25  1  0.616  0.999  0.810  1.0
  O  O26  1  0.908  0.249  0.069  1.0
  O  O27  1  0.389  0.551  0.751  1.0
  O  O28  1  0.810  0.616  0.999  1.0
  O  O29  1  0.551  0.751  0.389  1.0
  O  O30  1  0.753  0.949  0.103  1.0
  O  O31  1  0.751  0.389  0.552  1.0
  O  O32  1  0.020  0.149  0.406  1.0
  O  O33  1  0.500  0.889  0.687  1.0
  O  O34  1  0.949  0.103  0.753  1.0
  O  O35  1  0.687  0.500  0.889  1.0
  O  O36  1  0.889  0.687  0.500  1.0
[/CIF]
.