The compound described by Fe12As5 crystallizes in the trigonal R32 space group. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 14-coordinate geometry to two equivalent Fe(1), two equivalent Fe(3), six equivalent Fe(2), two equivalent As(1), and two equivalent As(2) atoms. In the second Fe site, Fe(2) is bonded in a 4-coordinate geometry to three equivalent Fe(1), two equivalent As(1), and two equivalent As(2) atoms. In the third Fe site, Fe(3) is bonded in a distorted trigonal non-coplanar geometry to three equivalent Fe(1) and three equivalent As(1) atoms. In the fourth Fe site, Fe(4) is bonded in a trigonal bipyramidal geometry to two equivalent As(2) and three equivalent As(1) atoms. There are two inequivalent As sites. In the first As site, As(1) is bonded in a 7-coordinate geometry to one Fe(4), two equivalent Fe(1), two equivalent Fe(3), and four equivalent Fe(2) atoms. In the second As site, As(2) is bonded in a 10-coordinate geometry to one Fe(4), three equivalent Fe(1), and six equivalent Fe(2) atoms. is represented by the CIF file [CIF]
data_Fe12As5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.657
_cell_length_b   6.657
_cell_length_c   6.657
_cell_angle_alpha   60.964
_cell_angle_beta   60.964
_cell_angle_gamma   60.964
_symmetry_Int_Tables_number   1
_cell_volume   213.156
_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
  Fe  Fe0  1  0.737  0.263  0.500  1.0
  Fe  Fe1  1  0.500  0.737  0.263  1.0
  Fe  Fe2  1  0.263  0.500  0.737  1.0
  Fe  Fe3  1  0.514  0.225  0.005  1.0
  Fe  Fe4  1  0.005  0.514  0.225  1.0
  Fe  Fe5  1  0.382  0.382  0.382  1.0
  Fe  Fe6  1  0.618  0.618  0.618  1.0
  Fe  Fe7  1  0.000  0.000  0.000  1.0
  Fe  Fe8  1  0.775  0.486  0.995  1.0
  Fe  Fe9  1  0.486  0.995  0.775  1.0
  Fe  Fe10  1  0.995  0.775  0.486  1.0
  Fe  Fe11  1  0.225  0.005  0.514  1.0
  As  As12  1  0.000  0.346  0.654  1.0
  As  As13  1  0.654  0.000  0.346  1.0
  As  As14  1  0.346  0.654  0.000  1.0
  As  As15  1  0.856  0.856  0.856  1.0
  As  As16  1  0.144  0.144  0.144  1.0
[/CIF]
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The compound described by Fe12As5 crystallizes in the trigonal R32 space group. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 14-coordinate geometry to two equivalent Fe(1), two equivalent Fe(3), six equivalent Fe(2), two equivalent As(1), and two equivalent As(2) atoms. In the second Fe site, Fe(2) is bonded in a 4-coordinate geometry to three equivalent Fe(1), two equivalent As(1), and two equivalent As(2) atoms. In the third Fe site, Fe(3) is bonded in a distorted trigonal non-coplanar geometry to three equivalent Fe(1) and three equivalent As(1) atoms. In the fourth Fe site, Fe(4) is bonded in a trigonal bipyramidal geometry to two equivalent As(2) and three equivalent As(1) atoms. There are two inequivalent As sites. In the first As site, As(1) is bonded in a 7-coordinate geometry to one Fe(4), two equivalent Fe(1), two equivalent Fe(3), and four equivalent Fe(2) atoms. In the second As site, As(2) is bonded in a 10-coordinate geometry to one Fe(4), three equivalent Fe(1), and six equivalent Fe(2) atoms. is represented by the CIF file [CIF]
data_Fe12As5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.657
_cell_length_b   6.657
_cell_length_c   6.657
_cell_angle_alpha   60.964
_cell_angle_beta   60.964
_cell_angle_gamma   60.964
_symmetry_Int_Tables_number   1
_cell_volume   213.156
_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
  Fe  Fe0  1  0.737  0.263  0.500  1.0
  Fe  Fe1  1  0.500  0.737  0.263  1.0
  Fe  Fe2  1  0.263  0.500  0.737  1.0
  Fe  Fe3  1  0.514  0.225  0.005  1.0
  Fe  Fe4  1  0.005  0.514  0.225  1.0
  Fe  Fe5  1  0.382  0.382  0.382  1.0
  Fe  Fe6  1  0.618  0.618  0.618  1.0
  Fe  Fe7  1  0.000  0.000  0.000  1.0
  Fe  Fe8  1  0.775  0.486  0.995  1.0
  Fe  Fe9  1  0.486  0.995  0.775  1.0
  Fe  Fe10  1  0.995  0.775  0.486  1.0
  Fe  Fe11  1  0.225  0.005  0.514  1.0
  As  As12  1  0.000  0.346  0.654  1.0
  As  As13  1  0.654  0.000  0.346  1.0
  As  As14  1  0.346  0.654  0.000  1.0
  As  As15  1  0.856  0.856  0.856  1.0
  As  As16  1  0.144  0.144  0.144  1.0
[/CIF]
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