data_Mg5Al2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   15.13
_cell_length_b   15.13
_cell_length_c   15.13
_cell_angle_alpha   168.52
_cell_angle_beta   168.52
_cell_angle_gamma   16.26
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Mg5Al2
_chemical_formula_sum   'Mg5 Al2'
_cell_volume   137.2
_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
  Mg  Mg3  1  0.0  0.0  0.28  1.0
  Mg  Mg4  1  0.0  0.0  0.4  1.0
  Mg  Mg5  1  0.0  0.0  0.56  1.0
  Mg  Mg6  1  0.0  0.0  0.68  1.0
  Al  Al0  1  0.0  0.0  0.84  1.0
  Al  Al1  1  0.0  0.0  0.12  1.0

data_Mg5Al2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.28
_cell_length_b   4.28
_cell_length_c   15.13
_cell_angle_alpha   90.0
_cell_angle_beta   98.13
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Mg5Al2
_chemical_formula_sum   'Mg10 Al4'
_cell_volume   274.41
_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
  Mg  Mg1  2  0.06  0.5  0.56  1.0
  Mg  Mg2  2  0.18  0.5  0.68  1.0
  Mg  Mg3  2  0.28  0.0  0.28  1.0
  Mg  Mg4  2  0.4  0.0  0.4  1.0
  Al  Al5  2  0.12  0.0  0.12  1.0
  Al  Al6  2  0.34  0.5  0.84  1.0

Mg Mg Mg Mg Mg Al Al
Mg Mg Mg Mg Mg Al Al 0 6 o o o 0 5 o o - 1 2 o o o 3 4 o o o 4 5 o o o 
Mg5Al2 crystallizes in the monoclinic Cm space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a distorted linear geometry to one Al(1) and one Al(2) atom. The Mg(1)-Al(1) bond length is 2.42 Å. The Mg(1)-Al(2) bond length is 1.82 Å. In the second Mg site, Mg(2,5) is bonded in a distorted linear geometry to one Mg(3) and one Al(2) atom. The Mg(2,5)-Mg(3) bond length is 1.82 Å. The Mg(2,5)-Al(2) bond length is 2.42 Å. In the third Mg site, Mg(3) is bonded in a 6-coordinate geometry to one Mg(2,5); one Mg(4); and four equivalent Mg(3) atoms. The Mg(3)-Mg(4) bond length is 2.42 Å. All Mg(3)-Mg(3) bond lengths are 3.03 Å. In the fourth Mg site, Mg(4) is bonded in a 6-coordinate geometry to one Mg(2,5); one Mg(3); and four equivalent Mg(4) atoms. The Mg(4)-Mg(2,5) bond length is 1.82 Å. All Mg(4)-Mg(4) bond lengths are 3.03 Å. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a linear geometry to one Mg(1) and one Mg(2,5) atom. The Al(1)-Mg(2,5) bond length is 2.42 Å. In the second Al site, Al(2) is bonded in a distorted linear geometry to one Mg(1) and one Mg(2,5) atom.