The crystal structure described by MgFe4(PO4)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(10), one O(11), one O(15), and one O(5) atom to form MgO4 tetrahedra that share  a cornercorner with one Fe(3)O4 tetrahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra,  a cornercorner with one Fe(1)O5 trigonal bipyramid, and  an edgeedge with one Fe(4)O4 tetrahedra. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(16), one O(5), one O(6), and one O(7) atom to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Fe(4)O4 tetrahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, and  an edgeedge with one P(1)O4 tetrahedra. In the second Fe site, Fe(2) is bonded to one O(2), one O(3), one O(4), one O(8), and one O(9) atom to form FeO5 trigonal bipyramids that share  a cornercorner with one Fe(3)O4 tetrahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, and  an edgeedge with one P(2)O4 tetrahedra. In the third Fe site, Fe(3) is bonded to one O(13), one O(14), one O(15), and one O(8) atom to form distorted FeO4 tetrahedra that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, and  a cornercorner with one Fe(2)O5 trigonal bipyramid. In the fourth Fe site, Fe(4) is bonded to one O(1), one O(10), one O(11), and one O(12) atom to form FeO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra,  a cornercorner with one Fe(1)O5 trigonal bipyramid, and  an edgeedge with one Mg(1)O4 tetrahedra. 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)O4 tetrahedra,  a cornercorner with one Fe(4)O4 tetrahedra,  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. 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  a cornercorner with one Fe(3)O4 tetrahedra,  a cornercorner with one Fe(1)O5 trigonal bipyramid,  a cornercorner with one Fe(2)O5 trigonal bipyramid, and  an edgeedge with one Fe(2)O5 trigonal bipyramid. 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  a cornercorner with one Fe(4)O4 tetrahedra, corners with two equivalent Mg(1)O4 tetrahedra, corners with two equivalent Fe(3)O4 tetrahedra, and  a cornercorner with one Fe(2)O5 trigonal bipyramid. 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)O4 tetrahedra,  a cornercorner with one Fe(3)O4 tetrahedra, corners with two equivalent Fe(4)O4 tetrahedra, and  a cornercorner with one Fe(1)O5 trigonal bipyramid. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(4), and one P(1) atom. In the second O site, O(2) is bonded in a water-like geometry to one Fe(2) and one P(2) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Fe(2) and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Fe(2) and one P(2) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Mg(1), 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 3-coordinate geometry to one Fe(2), one Fe(3), and one P(2) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Fe(2) and one P(3) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Mg(1), one Fe(4), and one P(3) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Mg(1), one Fe(4), and one P(4) atom. In the twelfth O site, O(12) is bonded in a bent 120 degrees geometry to one Fe(4) and one P(4) atom. In the thirteenth O site, O(13) is bonded in a bent 120 degrees geometry to one Fe(3) and one P(3) atom. In the fourteenth O site, O(14) is bonded in a bent 150 degrees geometry to one Fe(3) and one P(4) 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 bent 150 degrees geometry to one Fe(1) and one P(4) atom. is represented by the CIF card [CIF]
data_MgFe4(PO4)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.621
_cell_length_b   9.160
_cell_length_c   5.215
_cell_angle_alpha   87.538
_cell_angle_beta   108.189
_cell_angle_gamma   90.767
_symmetry_Int_Tables_number   1
_cell_volume   390.886
_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  0.604  0.658  0.850  1.0
  Fe  Fe1  1  0.208  0.476  0.466  1.0
  Fe  Fe2  1  0.294  0.989  0.044  1.0
  Fe  Fe3  1  0.696  0.037  0.848  1.0
  Fe  Fe4  1  0.846  0.518  0.621  1.0
  P  P5  1  0.230  0.652  0.910  1.0
  P  P6  1  0.299  0.149  0.608  1.0
  P  P7  1  0.652  0.844  0.360  1.0
  P  P8  1  0.825  0.358  0.144  1.0
  O  O9  1  0.087  0.564  0.708  1.0
  O  O10  1  0.165  0.121  0.745  1.0
  O  O11  1  0.179  0.812  0.892  1.0
  O  O12  1  0.250  0.093  0.322  1.0
  O  O13  1  0.369  0.621  0.788  1.0
  O  O14  1  0.271  0.586  0.199  1.0
  O  O15  1  0.345  0.313  0.602  1.0
  O  O16  1  0.447  0.061  0.811  1.0
  O  O17  1  0.468  0.877  0.294  1.0
  O  O18  1  0.682  0.694  0.524  1.0
  O  O19  1  0.750  0.488  0.934  1.0
  O  O20  1  0.750  0.364  0.374  1.0
  O  O21  1  0.754  0.963  0.535  1.0
  O  O22  1  0.800  0.214  0.005  1.0
  O  O23  1  0.692  0.828  0.089  1.0
  O  O24  1  0.012  0.393  0.252  1.0
[/CIF]
.
The crystal structure described by MgFe4(PO4)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(10), one O(11), one O(15), and one O(5) atom to form MgO4 tetrahedra that share  a cornercorner with one Fe(3)O4 tetrahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra,  a cornercorner with one Fe(1)O5 trigonal bipyramid, and  an edgeedge with one Fe(4)O4 tetrahedra. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(16), one O(5), one O(6), and one O(7) atom to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Fe(4)O4 tetrahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, and  an edgeedge with one P(1)O4 tetrahedra. In the second Fe site, Fe(2) is bonded to one O(2), one O(3), one O(4), one O(8), and one O(9) atom to form FeO5 trigonal bipyramids that share  a cornercorner with one Fe(3)O4 tetrahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, and  an edgeedge with one P(2)O4 tetrahedra. In the third Fe site, Fe(3) is bonded to one O(13), one O(14), one O(15), and one O(8) atom to form distorted FeO4 tetrahedra that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, and  a cornercorner with one Fe(2)O5 trigonal bipyramid. In the fourth Fe site, Fe(4) is bonded to one O(1), one O(10), one O(11), and one O(12) atom to form FeO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra,  a cornercorner with one Fe(1)O5 trigonal bipyramid, and  an edgeedge with one Mg(1)O4 tetrahedra. 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)O4 tetrahedra,  a cornercorner with one Fe(4)O4 tetrahedra,  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. 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  a cornercorner with one Fe(3)O4 tetrahedra,  a cornercorner with one Fe(1)O5 trigonal bipyramid,  a cornercorner with one Fe(2)O5 trigonal bipyramid, and  an edgeedge with one Fe(2)O5 trigonal bipyramid. 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  a cornercorner with one Fe(4)O4 tetrahedra, corners with two equivalent Mg(1)O4 tetrahedra, corners with two equivalent Fe(3)O4 tetrahedra, and  a cornercorner with one Fe(2)O5 trigonal bipyramid. 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)O4 tetrahedra,  a cornercorner with one Fe(3)O4 tetrahedra, corners with two equivalent Fe(4)O4 tetrahedra, and  a cornercorner with one Fe(1)O5 trigonal bipyramid. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(4), and one P(1) atom. In the second O site, O(2) is bonded in a water-like geometry to one Fe(2) and one P(2) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Fe(2) and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Fe(2) and one P(2) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Mg(1), 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 3-coordinate geometry to one Fe(2), one Fe(3), and one P(2) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Fe(2) and one P(3) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Mg(1), one Fe(4), and one P(3) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Mg(1), one Fe(4), and one P(4) atom. In the twelfth O site, O(12) is bonded in a bent 120 degrees geometry to one Fe(4) and one P(4) atom. In the thirteenth O site, O(13) is bonded in a bent 120 degrees geometry to one Fe(3) and one P(3) atom. In the fourteenth O site, O(14) is bonded in a bent 150 degrees geometry to one Fe(3) and one P(4) 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 bent 150 degrees geometry to one Fe(1) and one P(4) atom. is represented by the CIF card [CIF]
data_MgFe4(PO4)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.621
_cell_length_b   9.160
_cell_length_c   5.215
_cell_angle_alpha   87.538
_cell_angle_beta   108.189
_cell_angle_gamma   90.767
_symmetry_Int_Tables_number   1
_cell_volume   390.886
_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  0.604  0.658  0.850  1.0
  Fe  Fe1  1  0.208  0.476  0.466  1.0
  Fe  Fe2  1  0.294  0.989  0.044  1.0
  Fe  Fe3  1  0.696  0.037  0.848  1.0
  Fe  Fe4  1  0.846  0.518  0.621  1.0
  P  P5  1  0.230  0.652  0.910  1.0
  P  P6  1  0.299  0.149  0.608  1.0
  P  P7  1  0.652  0.844  0.360  1.0
  P  P8  1  0.825  0.358  0.144  1.0
  O  O9  1  0.087  0.564  0.708  1.0
  O  O10  1  0.165  0.121  0.745  1.0
  O  O11  1  0.179  0.812  0.892  1.0
  O  O12  1  0.250  0.093  0.322  1.0
  O  O13  1  0.369  0.621  0.788  1.0
  O  O14  1  0.271  0.586  0.199  1.0
  O  O15  1  0.345  0.313  0.602  1.0
  O  O16  1  0.447  0.061  0.811  1.0
  O  O17  1  0.468  0.877  0.294  1.0
  O  O18  1  0.682  0.694  0.524  1.0
  O  O19  1  0.750  0.488  0.934  1.0
  O  O20  1  0.750  0.364  0.374  1.0
  O  O21  1  0.754  0.963  0.535  1.0
  O  O22  1  0.800  0.214  0.005  1.0
  O  O23  1  0.692  0.828  0.089  1.0
  O  O24  1  0.012  0.393  0.252  1.0
[/CIF]
.