The crystal structure described by MgFe4As2O11 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 5-coordinate geometry to one O(10), one O(2), one O(3), one O(8), and one O(9) atom. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(10), one O(2), one O(3), one O(5), and one O(7) atom to form distorted FeO6 octahedra that share  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(4)O6 octahedra,  a cornercorner with one As(2)O4 tetrahedra, corners with two equivalent As(1)O4 tetrahedra,  an edgeedge with one Fe(2)O6 octahedra,  an edgeedge with one Fe(4)O6 octahedra, and edges with two equivalent Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-34°. In the second Fe site, Fe(2) is bonded to one O(1), one O(2), one O(3), one O(4), one O(8), and one O(9) atom to form distorted FeO6 octahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one As(1)O4 tetrahedra, corners with two equivalent As(2)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra,  an edgeedge with one Fe(3)O6 octahedra, and edges with two equivalent Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-23°. In the third Fe site, Fe(3) is bonded to one O(1), one O(10), one O(11), one O(2), one O(5), and one O(8) atom to form FeO6 octahedra that share  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent As(1)O4 tetrahedra, corners with two equivalent As(2)O4 tetrahedra,  an edgeedge with one Fe(2)O6 octahedra,  an edgeedge with one Fe(4)O6 octahedra, and edges with two equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles are 23°. In the fourth Fe site, Fe(4) is bonded to one O(1), one O(2), one O(4), one O(6), one O(7), and one O(9) atom to form FeO6 octahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent As(1)O4 tetrahedra, corners with two equivalent As(2)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra,  an edgeedge with one Fe(3)O6 octahedra, and edges with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles are 34°. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(11), one O(5), one O(7), and one O(9) atom to form AsO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, and corners with two equivalent Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-57°. In the second As site, As(2) is bonded to one O(10), one O(4), one O(6), and one O(8) atom to form AsO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, and corners with two equivalent Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-63°. There are eleven inequivalent O sites. In the first O site, O(1) is bonded to one Fe(1), one Fe(2), one Fe(3), and one Fe(4) atom to form edge-sharing OFe4 tetrahedra. In the second O site, O(2) is bonded to one Mg(1), one Fe(1), one Fe(2), one Fe(3), and one Fe(4) atom to form distorted edge-sharing OMgFe4 square pyramids. In the third O site, O(3) is bonded in a T-shaped geometry to one Mg(1), one Fe(1), and one Fe(2) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(4), and one As(2) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Fe(1), one Fe(3), and one As(1) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one Fe(4) and one As(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Fe(1), one Fe(4), and one As(1) atom. In the eighth O site, O(8) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Fe(2), one Fe(3), and one As(2) atom. In the ninth O site, O(9) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Fe(2), one Fe(4), and one As(1) atom. In the tenth O site, O(10) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Fe(1), one Fe(3), and one As(2) atom. In the eleventh O site, O(11) is bonded in a bent 120 degrees geometry to one Fe(3) and one As(1) atom. is represented by the CIF card [CIF]
data_MgFe4As2O11
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.422
_cell_length_b   6.596
_cell_length_c   6.953
_cell_angle_alpha   109.397
_cell_angle_beta   105.153
_cell_angle_gamma   96.283
_symmetry_Int_Tables_number   1
_cell_volume   221.063
_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  0.364  0.169  0.066  1.0
  Fe  Fe1  1  0.087  0.741  0.048  1.0
  Fe  Fe2  1  0.870  0.241  0.939  1.0
  Fe  Fe3  1  0.668  0.648  0.256  1.0
  Fe  Fe4  1  0.355  0.394  0.756  1.0
  As  As5  1  0.332  0.808  0.594  1.0
  As  As6  1  0.695  0.189  0.419  1.0
  O  O7  1  0.719  0.506  0.953  1.0
  O  O8  1  0.240  0.440  0.026  1.0
  O  O9  1  0.009  0.015  0.998  1.0
  O  O10  1  0.946  0.209  0.637  1.0
  O  O11  1  0.083  0.795  0.377  1.0
  O  O12  1  0.431  0.285  0.481  1.0
  O  O13  1  0.229  0.658  0.734  1.0
  O  O14  1  0.754  0.328  0.254  1.0
  O  O15  1  0.449  0.085  0.789  1.0
  O  O16  1  0.540  0.935  0.213  1.0
  O  O17  1  0.603  0.742  0.539  1.0
[/CIF]
.
The crystal structure described by MgFe4As2O11 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 5-coordinate geometry to one O(10), one O(2), one O(3), one O(8), and one O(9) atom. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(10), one O(2), one O(3), one O(5), and one O(7) atom to form distorted FeO6 octahedra that share  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(4)O6 octahedra,  a cornercorner with one As(2)O4 tetrahedra, corners with two equivalent As(1)O4 tetrahedra,  an edgeedge with one Fe(2)O6 octahedra,  an edgeedge with one Fe(4)O6 octahedra, and edges with two equivalent Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-34°. In the second Fe site, Fe(2) is bonded to one O(1), one O(2), one O(3), one O(4), one O(8), and one O(9) atom to form distorted FeO6 octahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one As(1)O4 tetrahedra, corners with two equivalent As(2)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra,  an edgeedge with one Fe(3)O6 octahedra, and edges with two equivalent Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-23°. In the third Fe site, Fe(3) is bonded to one O(1), one O(10), one O(11), one O(2), one O(5), and one O(8) atom to form FeO6 octahedra that share  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent As(1)O4 tetrahedra, corners with two equivalent As(2)O4 tetrahedra,  an edgeedge with one Fe(2)O6 octahedra,  an edgeedge with one Fe(4)O6 octahedra, and edges with two equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles are 23°. In the fourth Fe site, Fe(4) is bonded to one O(1), one O(2), one O(4), one O(6), one O(7), and one O(9) atom to form FeO6 octahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent As(1)O4 tetrahedra, corners with two equivalent As(2)O4 tetrahedra,  an edgeedge with one Fe(1)O6 octahedra,  an edgeedge with one Fe(3)O6 octahedra, and edges with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles are 34°. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(11), one O(5), one O(7), and one O(9) atom to form AsO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, and corners with two equivalent Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-57°. In the second As site, As(2) is bonded to one O(10), one O(4), one O(6), and one O(8) atom to form AsO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, and corners with two equivalent Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-63°. There are eleven inequivalent O sites. In the first O site, O(1) is bonded to one Fe(1), one Fe(2), one Fe(3), and one Fe(4) atom to form edge-sharing OFe4 tetrahedra. In the second O site, O(2) is bonded to one Mg(1), one Fe(1), one Fe(2), one Fe(3), and one Fe(4) atom to form distorted edge-sharing OMgFe4 square pyramids. In the third O site, O(3) is bonded in a T-shaped geometry to one Mg(1), one Fe(1), and one Fe(2) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(4), and one As(2) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Fe(1), one Fe(3), and one As(1) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one Fe(4) and one As(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Fe(1), one Fe(4), and one As(1) atom. In the eighth O site, O(8) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Fe(2), one Fe(3), and one As(2) atom. In the ninth O site, O(9) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Fe(2), one Fe(4), and one As(1) atom. In the tenth O site, O(10) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Fe(1), one Fe(3), and one As(2) atom. In the eleventh O site, O(11) is bonded in a bent 120 degrees geometry to one Fe(3) and one As(1) atom. is represented by the CIF card [CIF]
data_MgFe4As2O11
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.422
_cell_length_b   6.596
_cell_length_c   6.953
_cell_angle_alpha   109.397
_cell_angle_beta   105.153
_cell_angle_gamma   96.283
_symmetry_Int_Tables_number   1
_cell_volume   221.063
_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  0.364  0.169  0.066  1.0
  Fe  Fe1  1  0.087  0.741  0.048  1.0
  Fe  Fe2  1  0.870  0.241  0.939  1.0
  Fe  Fe3  1  0.668  0.648  0.256  1.0
  Fe  Fe4  1  0.355  0.394  0.756  1.0
  As  As5  1  0.332  0.808  0.594  1.0
  As  As6  1  0.695  0.189  0.419  1.0
  O  O7  1  0.719  0.506  0.953  1.0
  O  O8  1  0.240  0.440  0.026  1.0
  O  O9  1  0.009  0.015  0.998  1.0
  O  O10  1  0.946  0.209  0.637  1.0
  O  O11  1  0.083  0.795  0.377  1.0
  O  O12  1  0.431  0.285  0.481  1.0
  O  O13  1  0.229  0.658  0.734  1.0
  O  O14  1  0.754  0.328  0.254  1.0
  O  O15  1  0.449  0.085  0.789  1.0
  O  O16  1  0.540  0.935  0.213  1.0
  O  O17  1  0.603  0.742  0.539  1.0
[/CIF]
.