The compound described by BaFe2As2 crystallizes in the monoclinic C2/m space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a body-centered cubic geometry to four equivalent As(1) and four equivalent As(2) atoms. In the second Ba site, Ba(2) is bonded in a body-centered cubic geometry to four equivalent As(1) and four equivalent As(2) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one As(2) and three equivalent As(1) atoms to form a mixture of corner and edge-sharing FeAs4 tetrahedra. In the second Fe site, Fe(2) is bonded to one As(1) and three equivalent As(2) atoms to form a mixture of corner and edge-sharing FeAs4 tetrahedra. There are two inequivalent As sites. In the first As site, As(1) is bonded in a 8-coordinate geometry to two equivalent Ba(1), two equivalent Ba(2), one Fe(2), and three equivalent Fe(1) atoms. In the second As site, As(2) is bonded in a 8-coordinate geometry to two equivalent Ba(1), two equivalent Ba(2), one Fe(1), and three equivalent Fe(2) atoms. is represented by the CIF file [CIF]
data_Ba(FeAs)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.935
_cell_length_b   3.944
_cell_length_c   7.138
_cell_angle_alpha   74.410
_cell_angle_beta   74.020
_cell_angle_gamma   89.988
_symmetry_Int_Tables_number   1
_cell_volume   102.266
_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
  As  As0  1  0.650  0.645  0.700  1.0
  As  As1  1  0.350  0.355  0.300  1.0
  Ba  Ba2  1  0.000  0.000  1.000  1.0
  Fe  Fe3  1  0.251  0.758  0.499  1.0
  Fe  Fe4  1  0.749  0.242  0.501  1.0
[/CIF]
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The compound described by BaFe2As2 crystallizes in the monoclinic C2/m space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a body-centered cubic geometry to four equivalent As(1) and four equivalent As(2) atoms. In the second Ba site, Ba(2) is bonded in a body-centered cubic geometry to four equivalent As(1) and four equivalent As(2) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one As(2) and three equivalent As(1) atoms to form a mixture of corner and edge-sharing FeAs4 tetrahedra. In the second Fe site, Fe(2) is bonded to one As(1) and three equivalent As(2) atoms to form a mixture of corner and edge-sharing FeAs4 tetrahedra. There are two inequivalent As sites. In the first As site, As(1) is bonded in a 8-coordinate geometry to two equivalent Ba(1), two equivalent Ba(2), one Fe(2), and three equivalent Fe(1) atoms. In the second As site, As(2) is bonded in a 8-coordinate geometry to two equivalent Ba(1), two equivalent Ba(2), one Fe(1), and three equivalent Fe(2) atoms. is represented by the CIF file [CIF]
data_Ba(FeAs)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.935
_cell_length_b   3.944
_cell_length_c   7.138
_cell_angle_alpha   74.410
_cell_angle_beta   74.020
_cell_angle_gamma   89.988
_symmetry_Int_Tables_number   1
_cell_volume   102.266
_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
  As  As0  1  0.650  0.645  0.700  1.0
  As  As1  1  0.350  0.355  0.300  1.0
  Ba  Ba2  1  0.000  0.000  1.000  1.0
  Fe  Fe3  1  0.251  0.758  0.499  1.0
  Fe  Fe4  1  0.749  0.242  0.501  1.0
[/CIF]
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