The material structure described by MgFeAs2O7 crystallizes in the monoclinic C2 space group. Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with two equivalent As(1)O4 tetrahedra, edges with two equivalent As(1)O4 tetrahedra, and faces with two equivalent Fe(1)O6 octahedra. Fe(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted FeO6 octahedra that share corners with six equivalent As(1)O4 tetrahedra and faces with two equivalent Mg(1)O6 octahedra. As(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form AsO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra, corners with three equivalent Fe(1)O6 octahedra,  a cornercorner with one As(1)O4 tetrahedra, and  an edgeedge with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 22-59°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Mg(1), one Fe(1), and one As(1) 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 As(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(1), and one As(1) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to two equivalent As(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgFeAs2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.662
_cell_length_b   5.661
_cell_length_c   5.392
_cell_angle_alpha   79.348
_cell_angle_beta   100.637
_cell_angle_gamma   82.349
_symmetry_Int_Tables_number   1
_cell_volume   164.415
_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  0.132  0.132  0.500  1.0
  Fe  Fe1  1  0.097  0.097  0.000  1.0
  As  As2  1  0.644  0.283  0.403  1.0
  As  As3  1  0.283  0.644  0.597  1.0
  O  O4  1  0.825  0.091  0.676  1.0
  O  O5  1  0.841  0.321  0.200  1.0
  O  O6  1  0.377  0.195  0.283  1.0
  O  O7  1  0.091  0.825  0.324  1.0
  O  O8  1  0.321  0.841  0.800  1.0
  O  O9  1  0.195  0.377  0.717  1.0
  O  O10  1  0.566  0.566  0.500  1.0
[/CIF]
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The material structure described by MgFeAs2O7 crystallizes in the monoclinic C2 space group. Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with two equivalent As(1)O4 tetrahedra, edges with two equivalent As(1)O4 tetrahedra, and faces with two equivalent Fe(1)O6 octahedra. Fe(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted FeO6 octahedra that share corners with six equivalent As(1)O4 tetrahedra and faces with two equivalent Mg(1)O6 octahedra. As(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form AsO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra, corners with three equivalent Fe(1)O6 octahedra,  a cornercorner with one As(1)O4 tetrahedra, and  an edgeedge with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 22-59°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Mg(1), one Fe(1), and one As(1) 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 As(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(1), and one As(1) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to two equivalent As(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgFeAs2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.662
_cell_length_b   5.661
_cell_length_c   5.392
_cell_angle_alpha   79.348
_cell_angle_beta   100.637
_cell_angle_gamma   82.349
_symmetry_Int_Tables_number   1
_cell_volume   164.415
_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  0.132  0.132  0.500  1.0
  Fe  Fe1  1  0.097  0.097  0.000  1.0
  As  As2  1  0.644  0.283  0.403  1.0
  As  As3  1  0.283  0.644  0.597  1.0
  O  O4  1  0.825  0.091  0.676  1.0
  O  O5  1  0.841  0.321  0.200  1.0
  O  O6  1  0.377  0.195  0.283  1.0
  O  O7  1  0.091  0.825  0.324  1.0
  O  O8  1  0.321  0.841  0.800  1.0
  O  O9  1  0.195  0.377  0.717  1.0
  O  O10  1  0.566  0.566  0.500  1.0
[/CIF]
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