The structure described by MgFe2(PO4)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(3), one O(4), one O(5), one O(6), and one O(8) atom to form distorted MgO5 trigonal bipyramids that share corners with two equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  a cornercorner with one Fe(2)O5 trigonal bipyramid, corners with two equivalent Fe(1)O5 trigonal bipyramids, and  an edgeedge with one Fe(2)O5 trigonal bipyramid. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(2), one O(3), one O(5), and one O(7) atom to form FeO5 trigonal bipyramids that share corners with two equivalent P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, corners with two equivalent Mg(1)O5 trigonal bipyramids, and  an edgeedge with one Fe(2)O5 trigonal bipyramid. In the second Fe site, Fe(2) is bonded to one O(2), one O(4), one O(6), one O(7), and one O(8) atom to form distorted FeO5 trigonal bipyramids that share corners with two equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  a cornercorner with one Mg(1)O5 trigonal bipyramid,  an edgeedge with one Mg(1)O5 trigonal bipyramid, and  an edgeedge with one Fe(1)O5 trigonal bipyramid. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(3), one O(4), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Mg(1)O5 trigonal bipyramids, corners with two equivalent Fe(2)O5 trigonal bipyramids, and corners with three equivalent Fe(1)O5 trigonal bipyramids. In the second P site, P(2) is bonded to one O(2), one O(5), one O(6), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Fe(1)O5 trigonal bipyramids, corners with three equivalent Mg(1)O5 trigonal bipyramids, and corners with three equivalent Fe(2)O5 trigonal bipyramids. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Fe(1) and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Fe(1), one Fe(2), and one P(2) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Mg(1), one Fe(1), 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(1) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Mg(1), one Fe(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Mg(1), one Fe(2), and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(2), and one P(1) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(2), and one P(2) atom. is represented by the CIF file [CIF]
data_MgFe2(PO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.226
_cell_length_b   5.003
_cell_length_c   7.321
_cell_angle_alpha   76.453
_cell_angle_beta   60.885
_cell_angle_gamma   67.814
_symmetry_Int_Tables_number   1
_cell_volume   154.544
_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  0.389  0.547  0.068  1.0
  Fe  Fe1  1  0.047  0.778  0.706  1.0
  Fe  Fe2  1  0.927  0.197  0.321  1.0
  P  P3  1  0.357  0.141  0.792  1.0
  P  P4  1  0.639  0.863  0.220  1.0
  O  O5  1  0.166  0.351  0.682  1.0
  O  O6  1  0.302  0.869  0.379  1.0
  O  O7  1  0.303  0.841  0.840  1.0
  O  O8  1  0.270  0.257  0.001  1.0
  O  O9  1  0.699  0.743  0.022  1.0
  O  O10  1  0.657  0.177  0.186  1.0
  O  O11  1  0.707  0.106  0.644  1.0
  O  O12  1  0.886  0.660  0.296  1.0
[/CIF]
.
The structure described by MgFe2(PO4)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(3), one O(4), one O(5), one O(6), and one O(8) atom to form distorted MgO5 trigonal bipyramids that share corners with two equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  a cornercorner with one Fe(2)O5 trigonal bipyramid, corners with two equivalent Fe(1)O5 trigonal bipyramids, and  an edgeedge with one Fe(2)O5 trigonal bipyramid. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(2), one O(3), one O(5), and one O(7) atom to form FeO5 trigonal bipyramids that share corners with two equivalent P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, corners with two equivalent Mg(1)O5 trigonal bipyramids, and  an edgeedge with one Fe(2)O5 trigonal bipyramid. In the second Fe site, Fe(2) is bonded to one O(2), one O(4), one O(6), one O(7), and one O(8) atom to form distorted FeO5 trigonal bipyramids that share corners with two equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  a cornercorner with one Mg(1)O5 trigonal bipyramid,  an edgeedge with one Mg(1)O5 trigonal bipyramid, and  an edgeedge with one Fe(1)O5 trigonal bipyramid. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(3), one O(4), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Mg(1)O5 trigonal bipyramids, corners with two equivalent Fe(2)O5 trigonal bipyramids, and corners with three equivalent Fe(1)O5 trigonal bipyramids. In the second P site, P(2) is bonded to one O(2), one O(5), one O(6), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Fe(1)O5 trigonal bipyramids, corners with three equivalent Mg(1)O5 trigonal bipyramids, and corners with three equivalent Fe(2)O5 trigonal bipyramids. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Fe(1) and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Fe(1), one Fe(2), and one P(2) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Mg(1), one Fe(1), 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(1) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Mg(1), one Fe(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Mg(1), one Fe(2), and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(2), and one P(1) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(2), and one P(2) atom. is represented by the CIF file [CIF]
data_MgFe2(PO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.226
_cell_length_b   5.003
_cell_length_c   7.321
_cell_angle_alpha   76.453
_cell_angle_beta   60.885
_cell_angle_gamma   67.814
_symmetry_Int_Tables_number   1
_cell_volume   154.544
_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  0.389  0.547  0.068  1.0
  Fe  Fe1  1  0.047  0.778  0.706  1.0
  Fe  Fe2  1  0.927  0.197  0.321  1.0
  P  P3  1  0.357  0.141  0.792  1.0
  P  P4  1  0.639  0.863  0.220  1.0
  O  O5  1  0.166  0.351  0.682  1.0
  O  O6  1  0.302  0.869  0.379  1.0
  O  O7  1  0.303  0.841  0.840  1.0
  O  O8  1  0.270  0.257  0.001  1.0
  O  O9  1  0.699  0.743  0.022  1.0
  O  O10  1  0.657  0.177  0.186  1.0
  O  O11  1  0.707  0.106  0.644  1.0
  O  O12  1  0.886  0.660  0.296  1.0
[/CIF]
.