data_MgAlIr2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.05
_cell_length_b   3.05
_cell_length_c   6.2
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MgAlIr2
_chemical_formula_sum   'Mg1 Al1 Ir2'
_cell_volume   57.6
_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  Mg3  1  0.0  0.0  0.0  1.0
  Al  Al0  1  0.0  0.0  0.1  1.0
  Ir  Ir1  1  0.52  0.52  0.56  1.0
  Ir  Ir2  1  0.52  0.52  0.64  1.0

data_MgAlIr2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.31
_cell_length_b   4.31
_cell_length_c   6.2
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   MgAlIr2
_chemical_formula_sum   'Mg2 Al2 Ir4'
_cell_volume   115.2
_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
  Mg  Mg0  2  0.0  0.0  0.0  1.0
  Al  Al1  2  0.0  0.0  0.1  1.0
  Ir  Ir2  2  0.02  0.5  0.56  1.0
  Ir  Ir3  2  0.02  0.5  0.64  1.0

Mg Al Ir Ir
Mg Al Ir Ir 0 1 o o o 2 3 o o o 
MgAl(Ir)2 is alpha carbon monoxide-derived structured and crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two aluminum;magnesium molecules and two Ir clusters. In each Ir cluster, there are two inequivalent Ir sites. In the first Ir site, Ir(1) is bonded in a single-bond geometry to one Ir(2) atom. The Ir(1)-Ir(2) bond length is 0.54 Å. In the second Ir site, Ir(2) is bonded in a single-bond geometry to one Ir(1) atom.