The compound described by Mg3Fe3(PO4)4 crystallizes in the triclinic P1 space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(10), one O(12), one O(13), one O(15), one O(5), and one O(7) atom to form MgO6 octahedra that share  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra,  a cornercorner with one Mg(3)O5 trigonal bipyramid,  a cornercorner with one Fe(2)O5 trigonal bipyramid,  an edgeedge with one Fe(1)O5 trigonal bipyramid, and  an edgeedge with one Fe(3)O5 trigonal bipyramid. In the second Mg site, Mg(2) is bonded to one O(11), one O(14), one O(16), one O(6), one O(8), and one O(9) atom to form MgO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra,  a cornercorner with one Fe(1)O5 trigonal bipyramid,  a cornercorner with one Fe(3)O5 trigonal bipyramid,  an edgeedge with one Mg(3)O5 trigonal bipyramid, and  an edgeedge with one Fe(2)O5 trigonal bipyramid. In the third Mg site, Mg(3) is bonded to one O(1), one O(10), one O(14), one O(3), and one O(6) atom to form distorted MgO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one P(2)O4 tetrahedra, and  an edgeedge with one Fe(2)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 57°. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(13), one O(2), one O(4), one O(5), and one O(9) atom to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Mg(2)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  an edgeedge with one Mg(1)O6 octahedra,  an edgeedge with one P(1)O4 tetrahedra, and  an edgeedge with one Fe(3)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 60°. In the second Fe site, Fe(2) is bonded to one O(1), one O(12), one O(16), one O(3), and one O(8) atom to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one P(4)O4 tetrahedra, and  an edgeedge with one Mg(3)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 60°. In the third Fe site, Fe(3) is bonded to one O(11), one O(15), one O(2), one O(4), and one O(7) atom to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Mg(2)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  an edgeedge with one Mg(1)O6 octahedra,  an edgeedge with one P(3)O4 tetrahedra, and  an edgeedge with one Fe(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 60°. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(13), one O(5), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Mg(2)O6 octahedra, corners with two equivalent Mg(1)O6 octahedra,  a cornercorner with one Mg(3)O5 trigonal bipyramid,  a cornercorner with one Fe(1)O5 trigonal bipyramid,  a cornercorner with one Fe(2)O5 trigonal bipyramid, and  an edgeedge with one Fe(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 30-50°. In the second P site, P(2) is bonded to one O(10), one O(14), one O(2), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra, corners with two equivalent Mg(2)O6 octahedra,  a cornercorner with one Mg(3)O5 trigonal bipyramid,  a cornercorner with one Fe(1)O5 trigonal bipyramid,  a cornercorner with one Fe(3)O5 trigonal bipyramid, and  an edgeedge with one Mg(3)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 31-52°. In the third P site, P(3) is bonded to one O(11), one O(15), one O(3), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Mg(2)O6 octahedra, corners with two equivalent Mg(1)O6 octahedra,  a cornercorner with one Mg(3)O5 trigonal bipyramid,  a cornercorner with one Fe(2)O5 trigonal bipyramid,  a cornercorner with one Fe(3)O5 trigonal bipyramid, and  an edgeedge with one Fe(3)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 33-51°. In the fourth P site, P(4) is bonded to one O(12), one O(16), one O(4), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra, corners with two equivalent Mg(2)O6 octahedra,  a cornercorner with one Fe(1)O5 trigonal bipyramid,  a cornercorner with one Fe(2)O5 trigonal bipyramid,  a cornercorner with one Fe(3)O5 trigonal bipyramid, and  an edgeedge with one Fe(2)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 31-51°. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Mg(3), one Fe(2), and one P(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(3), and one P(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Mg(3), one Fe(2), and one P(3) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(3), and one P(4) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Mg(1), one Fe(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a T-shaped geometry to one Mg(2), one Mg(3), and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to one Mg(1), one Fe(3), and one P(3) atom. In the eighth O site, O(8) is bonded in a distorted T-shaped geometry to one Mg(2), one Fe(2), and one P(4) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Mg(2), one Fe(1), and one P(1) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mg(3), and one P(2) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Mg(2), one Fe(3), and one P(3) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Mg(1), one Fe(2), and one P(4) atom. In the thirteenth O site, O(13) is bonded in a distorted trigonal planar geometry to one Mg(1), one Fe(1), and one P(1) atom. In the fourteenth O site, O(14) is bonded in a 3-coordinate geometry to one Mg(2), one Mg(3), and one P(2) atom. In the fifteenth O site, O(15) is bonded in a distorted trigonal planar geometry to one Mg(1), one Fe(3), and one P(3) atom. In the sixteenth O site, O(16) is bonded in a distorted trigonal planar geometry to one Mg(2), one Fe(2), and one P(4) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg3Fe3(PO4)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.177
_cell_length_b   7.750
_cell_length_c   8.447
_cell_angle_alpha   89.905
_cell_angle_beta   89.893
_cell_angle_gamma   94.285
_symmetry_Int_Tables_number   1
_cell_volume   337.968
_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  0.000  0.501  0.501  1.0
  Mg  Mg1  1  0.502  0.999  0.999  1.0
  Mg  Mg2  1  0.410  0.889  0.646  1.0
  Fe  Fe3  1  0.912  0.384  0.854  1.0
  Fe  Fe4  1  0.585  0.115  0.354  1.0
  Fe  Fe5  1  0.086  0.619  0.147  1.0
  P  P6  1  0.466  0.299  0.692  1.0
  P  P7  1  0.968  0.800  0.804  1.0
  P  P8  1  0.532  0.701  0.311  1.0
  P  P9  1  0.032  0.200  0.192  1.0
  O  O10  1  0.448  0.139  0.581  1.0
  O  O11  1  0.952  0.644  0.921  1.0
  O  O12  1  0.543  0.855  0.428  1.0
  O  O13  1  0.049  0.359  0.079  1.0
  O  O14  1  0.682  0.434  0.637  1.0
  O  O15  1  0.189  0.935  0.855  1.0
  O  O16  1  0.317  0.562  0.361  1.0
  O  O17  1  0.817  0.064  0.138  1.0
  O  O18  1  0.549  0.243  0.862  1.0
  O  O19  1  0.058  0.740  0.638  1.0
  O  O20  1  0.450  0.761  0.142  1.0
  O  O21  1  0.949  0.257  0.361  1.0
  O  O22  1  0.200  0.379  0.692  1.0
  O  O23  1  0.702  0.878  0.802  1.0
  O  O24  1  0.800  0.624  0.309  1.0
  O  O25  1  0.299  0.121  0.192  1.0
[/CIF]
.
The compound described by Mg3Fe3(PO4)4 crystallizes in the triclinic P1 space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(10), one O(12), one O(13), one O(15), one O(5), and one O(7) atom to form MgO6 octahedra that share  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra,  a cornercorner with one Mg(3)O5 trigonal bipyramid,  a cornercorner with one Fe(2)O5 trigonal bipyramid,  an edgeedge with one Fe(1)O5 trigonal bipyramid, and  an edgeedge with one Fe(3)O5 trigonal bipyramid. In the second Mg site, Mg(2) is bonded to one O(11), one O(14), one O(16), one O(6), one O(8), and one O(9) atom to form MgO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra,  a cornercorner with one Fe(1)O5 trigonal bipyramid,  a cornercorner with one Fe(3)O5 trigonal bipyramid,  an edgeedge with one Mg(3)O5 trigonal bipyramid, and  an edgeedge with one Fe(2)O5 trigonal bipyramid. In the third Mg site, Mg(3) is bonded to one O(1), one O(10), one O(14), one O(3), and one O(6) atom to form distorted MgO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one P(2)O4 tetrahedra, and  an edgeedge with one Fe(2)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 57°. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(13), one O(2), one O(4), one O(5), and one O(9) atom to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Mg(2)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  an edgeedge with one Mg(1)O6 octahedra,  an edgeedge with one P(1)O4 tetrahedra, and  an edgeedge with one Fe(3)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 60°. In the second Fe site, Fe(2) is bonded to one O(1), one O(12), one O(16), one O(3), and one O(8) atom to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one P(4)O4 tetrahedra, and  an edgeedge with one Mg(3)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 60°. In the third Fe site, Fe(3) is bonded to one O(11), one O(15), one O(2), one O(4), and one O(7) atom to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Mg(2)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  an edgeedge with one Mg(1)O6 octahedra,  an edgeedge with one P(3)O4 tetrahedra, and  an edgeedge with one Fe(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 60°. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(13), one O(5), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Mg(2)O6 octahedra, corners with two equivalent Mg(1)O6 octahedra,  a cornercorner with one Mg(3)O5 trigonal bipyramid,  a cornercorner with one Fe(1)O5 trigonal bipyramid,  a cornercorner with one Fe(2)O5 trigonal bipyramid, and  an edgeedge with one Fe(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 30-50°. In the second P site, P(2) is bonded to one O(10), one O(14), one O(2), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra, corners with two equivalent Mg(2)O6 octahedra,  a cornercorner with one Mg(3)O5 trigonal bipyramid,  a cornercorner with one Fe(1)O5 trigonal bipyramid,  a cornercorner with one Fe(3)O5 trigonal bipyramid, and  an edgeedge with one Mg(3)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 31-52°. In the third P site, P(3) is bonded to one O(11), one O(15), one O(3), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Mg(2)O6 octahedra, corners with two equivalent Mg(1)O6 octahedra,  a cornercorner with one Mg(3)O5 trigonal bipyramid,  a cornercorner with one Fe(2)O5 trigonal bipyramid,  a cornercorner with one Fe(3)O5 trigonal bipyramid, and  an edgeedge with one Fe(3)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 33-51°. In the fourth P site, P(4) is bonded to one O(12), one O(16), one O(4), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra, corners with two equivalent Mg(2)O6 octahedra,  a cornercorner with one Fe(1)O5 trigonal bipyramid,  a cornercorner with one Fe(2)O5 trigonal bipyramid,  a cornercorner with one Fe(3)O5 trigonal bipyramid, and  an edgeedge with one Fe(2)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 31-51°. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Mg(3), one Fe(2), and one P(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(3), and one P(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Mg(3), one Fe(2), and one P(3) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(3), and one P(4) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Mg(1), one Fe(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a T-shaped geometry to one Mg(2), one Mg(3), and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to one Mg(1), one Fe(3), and one P(3) atom. In the eighth O site, O(8) is bonded in a distorted T-shaped geometry to one Mg(2), one Fe(2), and one P(4) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Mg(2), one Fe(1), and one P(1) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mg(3), and one P(2) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Mg(2), one Fe(3), and one P(3) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Mg(1), one Fe(2), and one P(4) atom. In the thirteenth O site, O(13) is bonded in a distorted trigonal planar geometry to one Mg(1), one Fe(1), and one P(1) atom. In the fourteenth O site, O(14) is bonded in a 3-coordinate geometry to one Mg(2), one Mg(3), and one P(2) atom. In the fifteenth O site, O(15) is bonded in a distorted trigonal planar geometry to one Mg(1), one Fe(3), and one P(3) atom. In the sixteenth O site, O(16) is bonded in a distorted trigonal planar geometry to one Mg(2), one Fe(2), and one P(4) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg3Fe3(PO4)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.177
_cell_length_b   7.750
_cell_length_c   8.447
_cell_angle_alpha   89.905
_cell_angle_beta   89.893
_cell_angle_gamma   94.285
_symmetry_Int_Tables_number   1
_cell_volume   337.968
_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  0.000  0.501  0.501  1.0
  Mg  Mg1  1  0.502  0.999  0.999  1.0
  Mg  Mg2  1  0.410  0.889  0.646  1.0
  Fe  Fe3  1  0.912  0.384  0.854  1.0
  Fe  Fe4  1  0.585  0.115  0.354  1.0
  Fe  Fe5  1  0.086  0.619  0.147  1.0
  P  P6  1  0.466  0.299  0.692  1.0
  P  P7  1  0.968  0.800  0.804  1.0
  P  P8  1  0.532  0.701  0.311  1.0
  P  P9  1  0.032  0.200  0.192  1.0
  O  O10  1  0.448  0.139  0.581  1.0
  O  O11  1  0.952  0.644  0.921  1.0
  O  O12  1  0.543  0.855  0.428  1.0
  O  O13  1  0.049  0.359  0.079  1.0
  O  O14  1  0.682  0.434  0.637  1.0
  O  O15  1  0.189  0.935  0.855  1.0
  O  O16  1  0.317  0.562  0.361  1.0
  O  O17  1  0.817  0.064  0.138  1.0
  O  O18  1  0.549  0.243  0.862  1.0
  O  O19  1  0.058  0.740  0.638  1.0
  O  O20  1  0.450  0.761  0.142  1.0
  O  O21  1  0.949  0.257  0.361  1.0
  O  O22  1  0.200  0.379  0.692  1.0
  O  O23  1  0.702  0.878  0.802  1.0
  O  O24  1  0.800  0.624  0.309  1.0
  O  O25  1  0.299  0.121  0.192  1.0
[/CIF]
.