The crystal structure described by MgFeP2O7 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a distorted pentagonal planar geometry to one O(2), one O(3), one O(4), one O(5), and one O(7) atom. Fe(1) is bonded to one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form distorted FeO5 trigonal bipyramids that share corners with two equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one P(2)O4 tetrahedra and corners with two equivalent Fe(1)O5 trigonal bipyramids. In the second P site, P(2) is bonded to one O(1), one O(2), one O(3), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra and corners with three equivalent Fe(1)O5 trigonal bipyramids. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Mg(1), one Fe(1), and one P(2) atom. In the third O site, O(3) is bonded in a T-shaped geometry to one Mg(1), one Fe(1), and one P(2) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Mg(1) and one P(1) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Fe(1) and one P(1) atom. In the seventh O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1), one Fe(1), and one P(2) atom. is represented by the CIF file [CIF]
data_MgFeP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.755
_cell_length_b   5.627
_cell_length_c   5.135
_cell_angle_alpha   96.888
_cell_angle_beta   110.922
_cell_angle_gamma   74.932
_symmetry_Int_Tables_number   1
_cell_volume   149.932
_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  0.495  0.190  0.879  1.0
  Fe  Fe1  1  0.095  0.038  0.058  1.0
  P  P2  1  0.299  0.686  0.570  1.0
  P  P3  1  0.650  0.287  0.425  1.0
  O  O4  1  0.578  0.573  0.522  1.0
  O  O5  1  0.808  0.266  0.237  1.0
  O  O6  1  0.402  0.209  0.240  1.0
  O  O7  1  0.338  0.906  0.780  1.0
  O  O8  1  0.249  0.484  0.697  1.0
  O  O9  1  0.112  0.768  0.283  1.0
  O  O10  1  0.772  0.141  0.697  1.0
[/CIF]
.
The crystal structure described by MgFeP2O7 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a distorted pentagonal planar geometry to one O(2), one O(3), one O(4), one O(5), and one O(7) atom. Fe(1) is bonded to one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form distorted FeO5 trigonal bipyramids that share corners with two equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one P(2)O4 tetrahedra and corners with two equivalent Fe(1)O5 trigonal bipyramids. In the second P site, P(2) is bonded to one O(1), one O(2), one O(3), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra and corners with three equivalent Fe(1)O5 trigonal bipyramids. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Mg(1), one Fe(1), and one P(2) atom. In the third O site, O(3) is bonded in a T-shaped geometry to one Mg(1), one Fe(1), and one P(2) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Mg(1) and one P(1) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Fe(1) and one P(1) atom. In the seventh O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1), one Fe(1), and one P(2) atom. is represented by the CIF file [CIF]
data_MgFeP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.755
_cell_length_b   5.627
_cell_length_c   5.135
_cell_angle_alpha   96.888
_cell_angle_beta   110.922
_cell_angle_gamma   74.932
_symmetry_Int_Tables_number   1
_cell_volume   149.932
_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  0.495  0.190  0.879  1.0
  Fe  Fe1  1  0.095  0.038  0.058  1.0
  P  P2  1  0.299  0.686  0.570  1.0
  P  P3  1  0.650  0.287  0.425  1.0
  O  O4  1  0.578  0.573  0.522  1.0
  O  O5  1  0.808  0.266  0.237  1.0
  O  O6  1  0.402  0.209  0.240  1.0
  O  O7  1  0.338  0.906  0.780  1.0
  O  O8  1  0.249  0.484  0.697  1.0
  O  O9  1  0.112  0.768  0.283  1.0
  O  O10  1  0.772  0.141  0.697  1.0
[/CIF]
.