data_Mg2AlB
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.94
_cell_length_b   3.94
_cell_length_c   3.96
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Mg2AlB
_chemical_formula_sum   'Mg2 Al1 B1'
_cell_volume   61.4
_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  0.97  0.98  1.0
  Mg  Mg3  1  0.97  0.0  0.98  1.0
  Al  Al0  1  0.97  0.97  0.0  1.0
  B  B1  1  0.0  0.0  0.0  1.0

data_Mg2AlB
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.57
_cell_length_b   5.57
_cell_length_c   3.96
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Mg2AlB
_chemical_formula_sum   'Mg4 Al2 B2'
_cell_volume   122.79
_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  4  0.48  0.48  0.98  1.0
  Al  Al1  2  0.47  0.5  -0.0  1.0
  B  B2  2  0.0  0.0  0.0  1.0

Mg Mg Al B
Mg2AlB is alpha Po structured and crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two Mg2AlB clusters. Mg(1) is bonded in a 2-coordinate geometry to one Al(1) and one B(1) atom. The Mg(1)-Al(1) bond length is 0.15 Å. The Mg(1)-B(1) bond length is 0.15 Å. Al(1) is bonded in a 3-coordinate geometry to two equivalent Mg(1) and one B(1) atom. The Al(1)-B(1) bond length is 0.17 Å. B(1) is bonded in a 3-coordinate geometry to two equivalent Mg(1) and one Al(1) atom.