The structure described by SrFeNi2(PO4)3 crystallizes in the orthorhombic Imma space group. Sr(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), and four equivalent O(3) atoms. Fe(1) is bonded to two equivalent O(1) and four equivalent O(4) atoms to form FeO6 octahedra that share corners with four equivalent Ni(1)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with four equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 57°. Ni(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  an edgeedge with one Ni(1)O6 octahedra, and  an edgeedge with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 57°. There are two inequivalent P sites. In the first P site, P(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form PO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with four equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-56°. In the second P site, P(2) is bonded to two equivalent O(3) and two equivalent O(4) atoms to form PO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Ni(1)O6 octahedra, and  an edgeedge with one Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-51°. There are four inequivalent O sites. In the first O site, O(2) is bonded in a 4-coordinate geometry to one Sr(1), two equivalent Ni(1), and one P(1) atom. In the second O site, O(3) is bonded in a 3-coordinate geometry to one Sr(1), one Ni(1), and one P(2) atom. In the third O site, O(4) is bonded in a distorted trigonal planar geometry to one Fe(1), one Ni(1), and one P(2) atom. In the fourth O site, O(1) is bonded in a 3-coordinate geometry to one Sr(1), one Fe(1), and one P(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_SrFeNi2(PO4)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.973
_cell_length_b   8.973
_cell_length_c   8.973
_cell_angle_alpha   137.521
_cell_angle_beta   109.381
_cell_angle_gamma   86.022
_symmetry_Int_Tables_number   1
_cell_volume   442.499
_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
  Sr  Sr0  1  0.250  0.340  0.090  1.0
  Sr  Sr1  1  0.750  0.660  0.910  1.0
  Fe  Fe2  1  0.000  0.500  0.500  1.0
  Fe  Fe3  1  0.500  0.000  0.500  1.0
  Ni  Ni4  1  0.116  0.116  0.500  1.0
  Ni  Ni5  1  0.384  0.884  0.000  1.0
  Ni  Ni6  1  0.616  0.116  0.000  1.0
  Ni  Ni7  1  0.884  0.884  0.500  1.0
  P  P8  1  0.250  0.835  0.585  1.0
  P  P9  1  0.750  0.165  0.415  1.0
  P  P10  1  0.322  0.322  0.500  1.0
  P  P11  1  0.178  0.678  0.000  1.0
  P  P12  1  0.822  0.322  0.000  1.0
  P  P13  1  0.678  0.678  0.500  1.0
  O  O14  1  0.344  0.793  0.449  1.0
  O  O15  1  0.656  0.207  0.551  1.0
  O  O16  1  0.844  0.396  0.551  1.0
  O  O17  1  0.156  0.604  0.449  1.0
  O  O18  1  0.132  0.980  0.612  1.0
  O  O19  1  0.632  0.020  0.151  1.0
  O  O20  1  0.868  0.020  0.388  1.0
  O  O21  1  0.368  0.980  0.849  1.0
  O  O22  1  0.348  0.202  0.277  1.0
  O  O23  1  0.076  0.798  0.146  1.0
  O  O24  1  0.848  0.570  0.146  1.0
  O  O25  1  0.576  0.430  0.277  1.0
  O  O26  1  0.652  0.798  0.723  1.0
  O  O27  1  0.924  0.202  0.854  1.0
  O  O28  1  0.152  0.430  0.854  1.0
  O  O29  1  0.424  0.570  0.723  1.0
  O  O30  1  0.132  0.287  0.431  1.0
  O  O31  1  0.144  0.713  0.845  1.0
  O  O32  1  0.632  0.201  0.845  1.0
  O  O33  1  0.644  0.799  0.431  1.0
  O  O34  1  0.868  0.713  0.569  1.0
  O  O35  1  0.856  0.287  0.155  1.0
  O  O36  1  0.368  0.799  0.155  1.0
  O  O37  1  0.356  0.201  0.569  1.0
[/CIF]
.
The structure described by SrFeNi2(PO4)3 crystallizes in the orthorhombic Imma space group. Sr(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), and four equivalent O(3) atoms. Fe(1) is bonded to two equivalent O(1) and four equivalent O(4) atoms to form FeO6 octahedra that share corners with four equivalent Ni(1)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with four equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 57°. Ni(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  an edgeedge with one Ni(1)O6 octahedra, and  an edgeedge with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 57°. There are two inequivalent P sites. In the first P site, P(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form PO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with four equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-56°. In the second P site, P(2) is bonded to two equivalent O(3) and two equivalent O(4) atoms to form PO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Ni(1)O6 octahedra, and  an edgeedge with one Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-51°. There are four inequivalent O sites. In the first O site, O(2) is bonded in a 4-coordinate geometry to one Sr(1), two equivalent Ni(1), and one P(1) atom. In the second O site, O(3) is bonded in a 3-coordinate geometry to one Sr(1), one Ni(1), and one P(2) atom. In the third O site, O(4) is bonded in a distorted trigonal planar geometry to one Fe(1), one Ni(1), and one P(2) atom. In the fourth O site, O(1) is bonded in a 3-coordinate geometry to one Sr(1), one Fe(1), and one P(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_SrFeNi2(PO4)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.973
_cell_length_b   8.973
_cell_length_c   8.973
_cell_angle_alpha   137.521
_cell_angle_beta   109.381
_cell_angle_gamma   86.022
_symmetry_Int_Tables_number   1
_cell_volume   442.499
_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
  Sr  Sr0  1  0.250  0.340  0.090  1.0
  Sr  Sr1  1  0.750  0.660  0.910  1.0
  Fe  Fe2  1  0.000  0.500  0.500  1.0
  Fe  Fe3  1  0.500  0.000  0.500  1.0
  Ni  Ni4  1  0.116  0.116  0.500  1.0
  Ni  Ni5  1  0.384  0.884  0.000  1.0
  Ni  Ni6  1  0.616  0.116  0.000  1.0
  Ni  Ni7  1  0.884  0.884  0.500  1.0
  P  P8  1  0.250  0.835  0.585  1.0
  P  P9  1  0.750  0.165  0.415  1.0
  P  P10  1  0.322  0.322  0.500  1.0
  P  P11  1  0.178  0.678  0.000  1.0
  P  P12  1  0.822  0.322  0.000  1.0
  P  P13  1  0.678  0.678  0.500  1.0
  O  O14  1  0.344  0.793  0.449  1.0
  O  O15  1  0.656  0.207  0.551  1.0
  O  O16  1  0.844  0.396  0.551  1.0
  O  O17  1  0.156  0.604  0.449  1.0
  O  O18  1  0.132  0.980  0.612  1.0
  O  O19  1  0.632  0.020  0.151  1.0
  O  O20  1  0.868  0.020  0.388  1.0
  O  O21  1  0.368  0.980  0.849  1.0
  O  O22  1  0.348  0.202  0.277  1.0
  O  O23  1  0.076  0.798  0.146  1.0
  O  O24  1  0.848  0.570  0.146  1.0
  O  O25  1  0.576  0.430  0.277  1.0
  O  O26  1  0.652  0.798  0.723  1.0
  O  O27  1  0.924  0.202  0.854  1.0
  O  O28  1  0.152  0.430  0.854  1.0
  O  O29  1  0.424  0.570  0.723  1.0
  O  O30  1  0.132  0.287  0.431  1.0
  O  O31  1  0.144  0.713  0.845  1.0
  O  O32  1  0.632  0.201  0.845  1.0
  O  O33  1  0.644  0.799  0.431  1.0
  O  O34  1  0.868  0.713  0.569  1.0
  O  O35  1  0.856  0.287  0.155  1.0
  O  O36  1  0.368  0.799  0.155  1.0
  O  O37  1  0.356  0.201  0.569  1.0
[/CIF]
.