The crystal structure described by MgFePO5 crystallizes in the triclinic P1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(1), one O(10), one O(3), one O(7), and one O(8) atom to form distorted MgO5 trigonal bipyramids that share corners with two equivalent Fe(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, edges with two equivalent Fe(2)O6 octahedra, and  an edgeedge with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 53-58°. In the second Mg site, Mg(2) is bonded to one O(2), one O(4), one O(5), one O(6), and one O(9) atom to form distorted MgO5 trigonal bipyramids that share corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra, and  an edgeedge with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 51-57°. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(10), one O(2), one O(4), one O(5), one O(7), and one O(9) atom to form FeO6 octahedra that share corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent Mg(1)O5 trigonal bipyramids, and edges with two equivalent Mg(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 46°. In the second Fe site, Fe(2) is bonded to one O(1), one O(10), one O(3), one O(6), one O(8), and one O(9) atom to form FeO6 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, corners with two equivalent Mg(2)O5 trigonal bipyramids, and edges with two equivalent Mg(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 46°. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(7), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one Mg(1)O5 trigonal bipyramid,  a cornercorner with one Mg(2)O5 trigonal bipyramid, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 37-51°. In the second P site, P(2) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one Mg(1)O5 trigonal bipyramid,  a cornercorner with one Mg(2)O5 trigonal bipyramid, and  an edgeedge with one Mg(2)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 36-50°. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(2), and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Mg(2), one Fe(1), and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(2), and one P(2) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Mg(2), one Fe(1), and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Mg(2), one Fe(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Mg(2), one Fe(2), and one P(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(1), and one P(1) atom. In the eighth O site, O(8) is bonded in a distorted T-shaped geometry to one Mg(1), one Fe(2), and one P(1) atom. In the ninth O site, O(9) is bonded in a trigonal planar geometry to one Mg(2), one Fe(1), and one Fe(2) atom. In the tenth O site, O(10) is bonded in a trigonal planar geometry to one Mg(1), one Fe(1), and one Fe(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgFePO5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.371
_cell_length_b   5.371
_cell_length_c   7.023
_cell_angle_alpha   105.029
_cell_angle_beta   105.033
_cell_angle_gamma   99.256
_symmetry_Int_Tables_number   1
_cell_volume   183.240
_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
  Mg  Mg0  1  0.390  0.241  0.819  1.0
  Mg  Mg1  1  0.753  0.885  0.322  1.0
  Fe  Fe2  1  0.998  0.507  0.512  1.0
  Fe  Fe3  1  0.014  0.487  0.012  1.0
  P  P4  1  0.642  0.829  0.755  1.0
  P  P5  1  0.337  0.130  0.256  1.0
  O  O6  1  0.670  0.615  0.866  1.0
  O  O7  1  0.808  0.804  0.603  1.0
  O  O8  1  0.303  0.285  0.097  1.0
  O  O9  1  0.123  0.159  0.367  1.0
  O  O10  1  0.622  0.227  0.416  1.0
  O  O11  1  0.328  0.835  0.147  1.0
  O  O12  1  0.349  0.815  0.639  1.0
  O  O13  1  0.731  0.115  0.915  1.0
  O  O14  1  0.908  0.582  0.253  1.0
  O  O15  1  0.093  0.404  0.755  1.0
[/CIF]
.
The crystal structure described by MgFePO5 crystallizes in the triclinic P1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(1), one O(10), one O(3), one O(7), and one O(8) atom to form distorted MgO5 trigonal bipyramids that share corners with two equivalent Fe(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, edges with two equivalent Fe(2)O6 octahedra, and  an edgeedge with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 53-58°. In the second Mg site, Mg(2) is bonded to one O(2), one O(4), one O(5), one O(6), and one O(9) atom to form distorted MgO5 trigonal bipyramids that share corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra, and  an edgeedge with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 51-57°. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(10), one O(2), one O(4), one O(5), one O(7), and one O(9) atom to form FeO6 octahedra that share corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent Mg(1)O5 trigonal bipyramids, and edges with two equivalent Mg(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 46°. In the second Fe site, Fe(2) is bonded to one O(1), one O(10), one O(3), one O(6), one O(8), and one O(9) atom to form FeO6 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, corners with two equivalent Mg(2)O5 trigonal bipyramids, and edges with two equivalent Mg(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 46°. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(7), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one Mg(1)O5 trigonal bipyramid,  a cornercorner with one Mg(2)O5 trigonal bipyramid, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 37-51°. In the second P site, P(2) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one Mg(1)O5 trigonal bipyramid,  a cornercorner with one Mg(2)O5 trigonal bipyramid, and  an edgeedge with one Mg(2)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 36-50°. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(2), and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Mg(2), one Fe(1), and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(2), and one P(2) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Mg(2), one Fe(1), and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Mg(2), one Fe(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Mg(2), one Fe(2), and one P(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(1), and one P(1) atom. In the eighth O site, O(8) is bonded in a distorted T-shaped geometry to one Mg(1), one Fe(2), and one P(1) atom. In the ninth O site, O(9) is bonded in a trigonal planar geometry to one Mg(2), one Fe(1), and one Fe(2) atom. In the tenth O site, O(10) is bonded in a trigonal planar geometry to one Mg(1), one Fe(1), and one Fe(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgFePO5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.371
_cell_length_b   5.371
_cell_length_c   7.023
_cell_angle_alpha   105.029
_cell_angle_beta   105.033
_cell_angle_gamma   99.256
_symmetry_Int_Tables_number   1
_cell_volume   183.240
_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
  Mg  Mg0  1  0.390  0.241  0.819  1.0
  Mg  Mg1  1  0.753  0.885  0.322  1.0
  Fe  Fe2  1  0.998  0.507  0.512  1.0
  Fe  Fe3  1  0.014  0.487  0.012  1.0
  P  P4  1  0.642  0.829  0.755  1.0
  P  P5  1  0.337  0.130  0.256  1.0
  O  O6  1  0.670  0.615  0.866  1.0
  O  O7  1  0.808  0.804  0.603  1.0
  O  O8  1  0.303  0.285  0.097  1.0
  O  O9  1  0.123  0.159  0.367  1.0
  O  O10  1  0.622  0.227  0.416  1.0
  O  O11  1  0.328  0.835  0.147  1.0
  O  O12  1  0.349  0.815  0.639  1.0
  O  O13  1  0.731  0.115  0.915  1.0
  O  O14  1  0.908  0.582  0.253  1.0
  O  O15  1  0.093  0.404  0.755  1.0
[/CIF]
.