The compound described by KFeNi(PO4)2 crystallizes in the monoclinic P2_1/c space group. K(1) is bonded in a 9-coordinate geometry to one O(2), one O(3), one O(4), one O(5), one O(7), two equivalent O(1), and two equivalent O(8) atoms. Fe(1) is bonded to one O(1), one O(2), one O(6), one O(7), and one O(8) atom to form FeO5 trigonal bipyramids that share  a cornercorner with one Ni(1)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with three equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 53°. Ni(1) is bonded to one O(4), one O(6), two equivalent O(3), and two equivalent O(5) atoms to form NiO6 octahedra that share  a cornercorner with one P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra,  a cornercorner with one Fe(1)O5 trigonal bipyramid, edges with two equivalent Ni(1)O6 octahedra, and  an edgeedge with one 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(3), and one O(4) atom to form PO4 tetrahedra that share corners with three equivalent Ni(1)O6 octahedra and corners with two equivalent Fe(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 56-58°. In the second P site, P(2) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Ni(1)O6 octahedra, corners with three equivalent Fe(1)O5 trigonal bipyramids, and  an edgeedge with one Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles are 4°. There are eight inequivalent O sites. In the first O site, O(4) is bonded in a 3-coordinate geometry to one K(1), one Ni(1), and one P(1) atom. In the second O site, O(5) is bonded in a 3-coordinate geometry to one K(1), two equivalent Ni(1), and one P(2) atom. In the third O site, O(6) is bonded in a 3-coordinate geometry to one Fe(1), one Ni(1), and one P(2) atom. In the fourth O site, O(7) is bonded in a 3-coordinate geometry to one K(1), one Fe(1), and one P(2) atom. In the fifth O site, O(8) is bonded in a 2-coordinate geometry to two equivalent K(1), one Fe(1), and one P(2) atom. In the sixth O site, O(1) is bonded in a 2-coordinate geometry to two equivalent K(1), one Fe(1), and one P(1) atom. In the seventh O site, O(2) is bonded in a distorted bent 150 degrees geometry to one K(1), one Fe(1), and one P(1) atom. In the eighth O site, O(3) is bonded in a 3-coordinate geometry to one K(1), two equivalent Ni(1), and one P(1) atom. is represented by the CIF file [CIF]
data_KFeNi(PO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   14.640
_cell_length_b   5.168
_cell_length_c   9.327
_cell_angle_alpha   75.295
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   682.550
_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
  K  K0  1  0.324  0.187  0.187  1.0
  K  K1  1  0.824  0.813  0.313  1.0
  K  K2  1  0.676  0.813  0.813  1.0
  K  K3  1  0.176  0.187  0.687  1.0
  Fe  Fe4  1  0.129  0.772  0.383  1.0
  Fe  Fe5  1  0.629  0.228  0.117  1.0
  Fe  Fe6  1  0.871  0.228  0.617  1.0
  Fe  Fe7  1  0.371  0.772  0.883  1.0
  Ni  Ni8  1  0.045  0.243  0.039  1.0
  Ni  Ni9  1  0.545  0.757  0.461  1.0
  Ni  Ni10  1  0.955  0.757  0.961  1.0
  Ni  Ni11  1  0.455  0.243  0.539  1.0
  P  P12  1  0.172  0.743  0.036  1.0
  P  P13  1  0.672  0.257  0.464  1.0
  P  P14  1  0.828  0.257  0.964  1.0
  P  P15  1  0.328  0.743  0.536  1.0
  P  P16  1  0.006  0.308  0.321  1.0
  P  P17  1  0.506  0.692  0.179  1.0
  P  P18  1  0.994  0.692  0.679  1.0
  P  P19  1  0.494  0.308  0.821  1.0
  O  O20  1  0.245  0.883  0.445  1.0
  O  O21  1  0.745  0.117  0.055  1.0
  O  O22  1  0.755  0.117  0.555  1.0
  O  O23  1  0.255  0.883  0.945  1.0
  O  O24  1  0.189  0.764  0.197  1.0
  O  O25  1  0.689  0.236  0.303  1.0
  O  O26  1  0.811  0.236  0.803  1.0
  O  O27  1  0.311  0.764  0.697  1.0
  O  O28  1  0.086  0.917  0.968  1.0
  O  O29  1  0.586  0.083  0.532  1.0
  O  O30  1  0.914  0.083  0.032  1.0
  O  O31  1  0.414  0.917  0.468  1.0
  O  O32  1  0.165  0.450  0.029  1.0
  O  O33  1  0.665  0.550  0.471  1.0
  O  O34  1  0.835  0.550  0.971  1.0
  O  O35  1  0.335  0.450  0.529  1.0
  O  O36  1  0.987  0.507  0.171  1.0
  O  O37  1  0.487  0.493  0.329  1.0
  O  O38  1  0.013  0.493  0.829  1.0
  O  O39  1  0.513  0.507  0.671  1.0
  O  O40  1  0.047  0.057  0.275  1.0
  O  O41  1  0.547  0.943  0.225  1.0
  O  O42  1  0.953  0.943  0.725  1.0
  O  O43  1  0.453  0.057  0.775  1.0
  O  O44  1  0.079  0.412  0.414  1.0
  O  O45  1  0.579  0.588  0.086  1.0
  O  O46  1  0.921  0.588  0.586  1.0
  O  O47  1  0.421  0.412  0.914  1.0
  O  O48  1  0.919  0.225  0.412  1.0
  O  O49  1  0.419  0.775  0.088  1.0
  O  O50  1  0.081  0.775  0.588  1.0
  O  O51  1  0.581  0.225  0.912  1.0
[/CIF]
.
The compound described by KFeNi(PO4)2 crystallizes in the monoclinic P2_1/c space group. K(1) is bonded in a 9-coordinate geometry to one O(2), one O(3), one O(4), one O(5), one O(7), two equivalent O(1), and two equivalent O(8) atoms. Fe(1) is bonded to one O(1), one O(2), one O(6), one O(7), and one O(8) atom to form FeO5 trigonal bipyramids that share  a cornercorner with one Ni(1)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with three equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 53°. Ni(1) is bonded to one O(4), one O(6), two equivalent O(3), and two equivalent O(5) atoms to form NiO6 octahedra that share  a cornercorner with one P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra,  a cornercorner with one Fe(1)O5 trigonal bipyramid, edges with two equivalent Ni(1)O6 octahedra, and  an edgeedge with one 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(3), and one O(4) atom to form PO4 tetrahedra that share corners with three equivalent Ni(1)O6 octahedra and corners with two equivalent Fe(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 56-58°. In the second P site, P(2) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Ni(1)O6 octahedra, corners with three equivalent Fe(1)O5 trigonal bipyramids, and  an edgeedge with one Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles are 4°. There are eight inequivalent O sites. In the first O site, O(4) is bonded in a 3-coordinate geometry to one K(1), one Ni(1), and one P(1) atom. In the second O site, O(5) is bonded in a 3-coordinate geometry to one K(1), two equivalent Ni(1), and one P(2) atom. In the third O site, O(6) is bonded in a 3-coordinate geometry to one Fe(1), one Ni(1), and one P(2) atom. In the fourth O site, O(7) is bonded in a 3-coordinate geometry to one K(1), one Fe(1), and one P(2) atom. In the fifth O site, O(8) is bonded in a 2-coordinate geometry to two equivalent K(1), one Fe(1), and one P(2) atom. In the sixth O site, O(1) is bonded in a 2-coordinate geometry to two equivalent K(1), one Fe(1), and one P(1) atom. In the seventh O site, O(2) is bonded in a distorted bent 150 degrees geometry to one K(1), one Fe(1), and one P(1) atom. In the eighth O site, O(3) is bonded in a 3-coordinate geometry to one K(1), two equivalent Ni(1), and one P(1) atom. is represented by the CIF file [CIF]
data_KFeNi(PO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   14.640
_cell_length_b   5.168
_cell_length_c   9.327
_cell_angle_alpha   75.295
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   682.550
_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
  K  K0  1  0.324  0.187  0.187  1.0
  K  K1  1  0.824  0.813  0.313  1.0
  K  K2  1  0.676  0.813  0.813  1.0
  K  K3  1  0.176  0.187  0.687  1.0
  Fe  Fe4  1  0.129  0.772  0.383  1.0
  Fe  Fe5  1  0.629  0.228  0.117  1.0
  Fe  Fe6  1  0.871  0.228  0.617  1.0
  Fe  Fe7  1  0.371  0.772  0.883  1.0
  Ni  Ni8  1  0.045  0.243  0.039  1.0
  Ni  Ni9  1  0.545  0.757  0.461  1.0
  Ni  Ni10  1  0.955  0.757  0.961  1.0
  Ni  Ni11  1  0.455  0.243  0.539  1.0
  P  P12  1  0.172  0.743  0.036  1.0
  P  P13  1  0.672  0.257  0.464  1.0
  P  P14  1  0.828  0.257  0.964  1.0
  P  P15  1  0.328  0.743  0.536  1.0
  P  P16  1  0.006  0.308  0.321  1.0
  P  P17  1  0.506  0.692  0.179  1.0
  P  P18  1  0.994  0.692  0.679  1.0
  P  P19  1  0.494  0.308  0.821  1.0
  O  O20  1  0.245  0.883  0.445  1.0
  O  O21  1  0.745  0.117  0.055  1.0
  O  O22  1  0.755  0.117  0.555  1.0
  O  O23  1  0.255  0.883  0.945  1.0
  O  O24  1  0.189  0.764  0.197  1.0
  O  O25  1  0.689  0.236  0.303  1.0
  O  O26  1  0.811  0.236  0.803  1.0
  O  O27  1  0.311  0.764  0.697  1.0
  O  O28  1  0.086  0.917  0.968  1.0
  O  O29  1  0.586  0.083  0.532  1.0
  O  O30  1  0.914  0.083  0.032  1.0
  O  O31  1  0.414  0.917  0.468  1.0
  O  O32  1  0.165  0.450  0.029  1.0
  O  O33  1  0.665  0.550  0.471  1.0
  O  O34  1  0.835  0.550  0.971  1.0
  O  O35  1  0.335  0.450  0.529  1.0
  O  O36  1  0.987  0.507  0.171  1.0
  O  O37  1  0.487  0.493  0.329  1.0
  O  O38  1  0.013  0.493  0.829  1.0
  O  O39  1  0.513  0.507  0.671  1.0
  O  O40  1  0.047  0.057  0.275  1.0
  O  O41  1  0.547  0.943  0.225  1.0
  O  O42  1  0.953  0.943  0.725  1.0
  O  O43  1  0.453  0.057  0.775  1.0
  O  O44  1  0.079  0.412  0.414  1.0
  O  O45  1  0.579  0.588  0.086  1.0
  O  O46  1  0.921  0.588  0.586  1.0
  O  O47  1  0.421  0.412  0.914  1.0
  O  O48  1  0.919  0.225  0.412  1.0
  O  O49  1  0.419  0.775  0.088  1.0
  O  O50  1  0.081  0.775  0.588  1.0
  O  O51  1  0.581  0.225  0.912  1.0
[/CIF]
.