data_FeIrSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.89
_cell_length_b   2.89
_cell_length_c   8.55
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.19
_symmetry_Int_Tables_number   1
_chemical_formula_structural   FeIrSe2
_chemical_formula_sum   'Fe1 Ir1 Se2'
_cell_volume   61.9
_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  0.0  0.0  0.0  1.0
  Ir  Ir1  1  0.0  0.0  0.27  1.0
  Se  Se2  1  0.44  0.0  0.6  1.0
  Se  Se3  1  0.44  0.0  0.95  1.0

data_FeIrSe2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   2.89
_cell_length_b   5.0
_cell_length_c   8.55
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   FeIrSe2
_chemical_formula_sum   'Fe2 Ir2 Se4'
_cell_volume   123.8
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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  2  0.0  0.0  0.0  1.0
  Ir  Ir1  2  0.0  0.0  0.73  1.0
  Se  Se2  2  0.06  0.5  0.05  1.0
  Se  Se3  2  0.06  0.5  0.4  1.0

Fe Ir Se Se
Fe Ir Se Se 0 3 o o - 0 1 o o o 1 1 + + o 1 1 o + o 1 1 + o o 1 3 - o - 1 3 o o - 1 2 - o o 1 2 o o o 2 2 + + o 2 2 o + o 2 2 + o o 2 3 o o o 
FeIrSe2 crystallizes in the monoclinic Cm space group. Fe(1) is bonded in a distorted bent 150 degrees geometry to one Ir(1) and two equivalent Se(2) atoms. The Fe(1)-Ir(1) bond length is 2.33 Å. There is one shorter (1.35 Å) and one longer (1.67 Å) Fe(1)-Se(2) bond length. Ir(1) is bonded in a distorted single-bond geometry to one Fe(1) and two equivalent Se(1) atoms. There is one shorter (3.05 Å) and one longer (3.20 Å) Ir(1)-Se(1) bond length. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 9-coordinate geometry to two equivalent Ir(1), one Se(2), and six equivalent Se(1) atoms. The Se(1)-Se(2) bond length is 3.02 Å. All Se(1)-Se(1) bond lengths are 2.89 Å. In the second Se site, Se(2) is bonded in a distorted bent 150 degrees geometry to two equivalent Fe(1) and one Se(1) atom.