The structure described by MgFe4(PO4)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(13), one O(14), one O(15), one O(2), one O(3), and one O(4) atom to form MgO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  an edgeedge with one P(2)O4 tetrahedra, and  an edgeedge with one P(3)O4 tetrahedra. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 5-coordinate geometry to one O(1), one O(16), one O(5), one O(6), and one O(7) atom. In the second Fe site, Fe(2) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(4), one O(8), and one O(9) atom. In the third Fe site, Fe(3) is bonded in a 5-coordinate geometry to one O(13), one O(14), one O(15), one O(8), and one O(9) atom. In the fourth Fe site, Fe(4) is bonded in a 5-coordinate geometry to one O(1), one O(10), one O(11), one O(12), and one O(16) atom. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles are 44°. In the second P site, P(2) is bonded to one O(2), one O(4), one O(7), and one O(8) atom to form PO4 tetrahedra that share  an edgeedge with one Mg(1)O6 octahedra. In the third P site, P(3) is bonded to one O(10), one O(13), one O(15), and one O(9) atom to form PO4 tetrahedra that share  an edgeedge with one Mg(1)O6 octahedra. In the fourth P site, P(4) is bonded to one O(11), one O(12), one O(14), and one O(16) atom to form PO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles are 43°. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Fe(1), one Fe(4), and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(2), and one P(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Mg(1), one Fe(2), and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(2), and one P(2) atom. In the fifth O site, O(5) is bonded in a water-like geometry to one Fe(1) and one P(1) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(1) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Fe(1) and one P(2) atom. In the eighth O site, O(8) is bonded in a distorted T-shaped geometry to one Fe(2), one Fe(3), and one P(2) atom. In the ninth O site, O(9) is bonded in a distorted T-shaped geometry to one Fe(2), one Fe(3), and one P(3) atom. In the tenth O site, O(10) is bonded in a bent 120 degrees geometry to one Fe(4) and one P(3) atom. In the eleventh O site, O(11) is bonded in a bent 150 degrees geometry to one Fe(4) and one P(4) atom. In the twelfth O site, O(12) is bonded in a water-like geometry to one Fe(4) and one P(4) atom. In the thirteenth O site, O(13) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(3), and one P(3) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal planar geometry to one Mg(1), one Fe(3), and one P(4) atom. In the fifteenth O site, O(15) is bonded in a 3-coordinate 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 T-shaped geometry to one Fe(1), one Fe(4), and one P(4) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgFe4(PO4)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.141
_cell_length_b   8.805
_cell_length_c   5.304
_cell_angle_alpha   86.372
_cell_angle_beta   105.734
_cell_angle_gamma   90.943
_symmetry_Int_Tables_number   1
_cell_volume   365.231
_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  0.998  0.002  0.497  1.0
  Fe  Fe1  1  0.200  0.512  0.439  1.0
  Fe  Fe2  1  0.308  0.005  0.056  1.0
  Fe  Fe3  1  0.689  0.997  0.938  1.0
  Fe  Fe4  1  0.805  0.491  0.538  1.0
  P  P5  1  0.187  0.679  0.847  1.0
  P  P6  1  0.292  0.167  0.587  1.0
  P  P7  1  0.707  0.835  0.408  1.0
  P  P8  1  0.818  0.325  0.128  1.0
  O  O9  1  0.035  0.585  0.676  1.0
  O  O10  1  0.147  0.160  0.729  1.0
  O  O11  1  0.148  0.851  0.808  1.0
  O  O12  1  0.224  0.061  0.355  1.0
  O  O13  1  0.331  0.634  0.725  1.0
  O  O14  1  0.223  0.630  0.140  1.0
  O  O15  1  0.329  0.329  0.488  1.0
  O  O16  1  0.451  0.097  0.788  1.0
  O  O17  1  0.546  0.902  0.208  1.0
  O  O18  1  0.675  0.672  0.510  1.0
  O  O19  1  0.786  0.366  0.833  1.0
  O  O20  1  0.673  0.379  0.242  1.0
  O  O21  1  0.773  0.942  0.639  1.0
  O  O22  1  0.850  0.152  0.180  1.0
  O  O23  1  0.851  0.844  0.265  1.0
  O  O24  1  0.972  0.417  0.298  1.0
[/CIF]
.
The structure described by MgFe4(PO4)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(13), one O(14), one O(15), one O(2), one O(3), and one O(4) atom to form MgO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  an edgeedge with one P(2)O4 tetrahedra, and  an edgeedge with one P(3)O4 tetrahedra. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 5-coordinate geometry to one O(1), one O(16), one O(5), one O(6), and one O(7) atom. In the second Fe site, Fe(2) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(4), one O(8), and one O(9) atom. In the third Fe site, Fe(3) is bonded in a 5-coordinate geometry to one O(13), one O(14), one O(15), one O(8), and one O(9) atom. In the fourth Fe site, Fe(4) is bonded in a 5-coordinate geometry to one O(1), one O(10), one O(11), one O(12), and one O(16) atom. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles are 44°. In the second P site, P(2) is bonded to one O(2), one O(4), one O(7), and one O(8) atom to form PO4 tetrahedra that share  an edgeedge with one Mg(1)O6 octahedra. In the third P site, P(3) is bonded to one O(10), one O(13), one O(15), and one O(9) atom to form PO4 tetrahedra that share  an edgeedge with one Mg(1)O6 octahedra. In the fourth P site, P(4) is bonded to one O(11), one O(12), one O(14), and one O(16) atom to form PO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles are 43°. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Fe(1), one Fe(4), and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(2), and one P(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Mg(1), one Fe(2), and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(2), and one P(2) atom. In the fifth O site, O(5) is bonded in a water-like geometry to one Fe(1) and one P(1) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(1) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Fe(1) and one P(2) atom. In the eighth O site, O(8) is bonded in a distorted T-shaped geometry to one Fe(2), one Fe(3), and one P(2) atom. In the ninth O site, O(9) is bonded in a distorted T-shaped geometry to one Fe(2), one Fe(3), and one P(3) atom. In the tenth O site, O(10) is bonded in a bent 120 degrees geometry to one Fe(4) and one P(3) atom. In the eleventh O site, O(11) is bonded in a bent 150 degrees geometry to one Fe(4) and one P(4) atom. In the twelfth O site, O(12) is bonded in a water-like geometry to one Fe(4) and one P(4) atom. In the thirteenth O site, O(13) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(3), and one P(3) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal planar geometry to one Mg(1), one Fe(3), and one P(4) atom. In the fifteenth O site, O(15) is bonded in a 3-coordinate 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 T-shaped geometry to one Fe(1), one Fe(4), and one P(4) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgFe4(PO4)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.141
_cell_length_b   8.805
_cell_length_c   5.304
_cell_angle_alpha   86.372
_cell_angle_beta   105.734
_cell_angle_gamma   90.943
_symmetry_Int_Tables_number   1
_cell_volume   365.231
_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  0.998  0.002  0.497  1.0
  Fe  Fe1  1  0.200  0.512  0.439  1.0
  Fe  Fe2  1  0.308  0.005  0.056  1.0
  Fe  Fe3  1  0.689  0.997  0.938  1.0
  Fe  Fe4  1  0.805  0.491  0.538  1.0
  P  P5  1  0.187  0.679  0.847  1.0
  P  P6  1  0.292  0.167  0.587  1.0
  P  P7  1  0.707  0.835  0.408  1.0
  P  P8  1  0.818  0.325  0.128  1.0
  O  O9  1  0.035  0.585  0.676  1.0
  O  O10  1  0.147  0.160  0.729  1.0
  O  O11  1  0.148  0.851  0.808  1.0
  O  O12  1  0.224  0.061  0.355  1.0
  O  O13  1  0.331  0.634  0.725  1.0
  O  O14  1  0.223  0.630  0.140  1.0
  O  O15  1  0.329  0.329  0.488  1.0
  O  O16  1  0.451  0.097  0.788  1.0
  O  O17  1  0.546  0.902  0.208  1.0
  O  O18  1  0.675  0.672  0.510  1.0
  O  O19  1  0.786  0.366  0.833  1.0
  O  O20  1  0.673  0.379  0.242  1.0
  O  O21  1  0.773  0.942  0.639  1.0
  O  O22  1  0.850  0.152  0.180  1.0
  O  O23  1  0.851  0.844  0.265  1.0
  O  O24  1  0.972  0.417  0.298  1.0
[/CIF]
.