data_MgIr2Se
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.0
_cell_length_b   3.0
_cell_length_c   6.98
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MgIr2Se
_chemical_formula_sum   'Mg1 Ir2 Se1'
_cell_volume   63.02
_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  Mg2  1  0.0  0.0  0.0  1.0
  Ir  Ir0  1  0.5  0.5  0.14  1.0
  Ir  Ir1  1  0.5  0.5  0.84  1.0
  Se  Se3  1  0.0  0.0  0.49  1.0

data_MgIr2Se
_symmetry_space_group_name_H-M   P4mm
_cell_length_a   3.0
_cell_length_b   3.0
_cell_length_c   6.98
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   99
_chemical_formula_structural   MgIr2Se
_chemical_formula_sum   'Mg1 Ir2 Se1'
_cell_volume   63.02
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-y, x, z'
  3  '-x, -y, z'
  4  'y, -x, z'
  5  '-x, y, z'
  6  'y, x, z'
  7  'x, -y, z'
  8  '-y, -x, 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  0.0  0.0  0.0  1.0
  Ir  Ir1  1  0.5  0.5  0.14  1.0
  Ir  Ir2  1  0.5  0.5  0.84  1.0
  Se  Se3  1  0.0  0.0  0.49  1.0

Mg Ir Ir Se
MgIr2Se crystallizes in the monoclinic Cm space group. Mg(1) is bonded in a body-centered cubic geometry to four equivalent Ir(1) and four equivalent Ir(2) atoms. There are a spread of Mg(1)-Ir(1) bond distances ranging from 2.34-2.36 Å. There are a spread of Mg(1)-Ir(2) bond distances ranging from 2.40-2.42 Å. There are two inequivalent Ir sites. In the first Ir site, Ir(1) is bonded in a 4-coordinate geometry to four equivalent Mg(1) and four equivalent Se(1) atoms. There is one shorter (3.21 Å) and three longer (3.22 Å) Ir(1)-Se(1) bond lengths. In the second Ir site, Ir(2) is bonded in a 4-coordinate geometry to four equivalent Mg(1) and four equivalent Se(1) atoms. There is one shorter (3.21 Å) and three longer (3.22 Å) Ir(2)-Se(1) bond lengths. Se(1) is bonded to four equivalent Ir(1), four equivalent Ir(2), and four equivalent Se(1) atoms to form a mixture of distorted corner and face-sharing SeIr8Se4 cuboctahedra. All Se(1)-Se(1) bond lengths are 3.00 Å.