data_Sr2Al
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.84
_cell_length_b   5.53
_cell_length_c   10.42
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Sr2Al
_chemical_formula_sum   'Sr8 Al4'
_cell_volume   451.53
_cell_formula_units_Z   4
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
  Sr  Sr4  1  0.15  0.38  0.25  1.0
  Sr  Sr5  1  0.61  0.14  0.46  1.0
  Sr  Sr6  1  0.23  0.38  0.96  1.0
  Sr  Sr7  1  0.69  0.14  0.17  1.0
  Sr  Sr8  1  0.18  0.38  0.7  1.0
  Sr  Sr9  1  0.58  0.14  0.49  1.0
  Sr  Sr10  1  0.26  0.38  0.93  1.0
  Sr  Sr11  1  0.66  0.14  0.72  1.0
  Al  Al0  1  0.83  0.38  0.24  1.0
  Al  Al1  1  0.09  0.14  0.03  1.0
  Al  Al2  1  0.75  0.38  0.39  1.0
  Al  Al3  1  0.01  0.14  0.18  1.0

data_Sr2Al
_symmetry_space_group_name_H-M   P-1
_cell_length_a   5.53
_cell_length_b   7.84
_cell_length_c   10.42
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   2
_chemical_formula_structural   Sr2Al
_chemical_formula_sum   'Sr8 Al4'
_cell_volume   451.53
_cell_formula_units_Z   4
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-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
  Sr  Sr0  2  0.38  0.66  0.78  1.0
  Sr  Sr1  2  0.38  0.69  0.75  1.0
  Sr  Sr2  2  0.38  0.74  0.01  1.0
  Sr  Sr3  2  0.38  0.77  0.46  1.0
  Al  Al4  2  0.38  0.09  0.47  1.0
  Al  Al5  2  0.38  0.17  0.32  1.0

Sr Sr Sr Sr Sr Sr Sr Sr Al Al Al Al
Sr Sr Sr Sr Sr Sr Sr Sr Al Al Al Al 0 11 o o o 1 5 o o o 1 7 o o o 1 10 o o o 2 6 o o o 2 4 o o o 2 9 o o + 3 8 o o o 4 6 o o o 5 7 o o o 8 10 o o o 9 11 o o o 
Sr2Al is Indium-like structured and crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of one Sr2Al cluster. There are four inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 2-coordinate geometry to two equivalent Al(1) atoms. There is one shorter (1.89 Å) and one longer (2.51 Å) Sr(1)-Al(1) bond length. In the second Sr site, Sr(2) is bonded in a distorted bent 120 degrees geometry to one Sr(4) and one Al(2) atom. The Sr(2)-Sr(4) bond length is 0.40 Å. The Sr(2)-Al(2) bond length is 1.89 Å. In the third Sr site, Sr(3) is bonded in a single-bond geometry to one Sr(4) atom. The Sr(3)-Sr(4) bond length is 2.44 Å. In the fourth Sr site, Sr(4) is bonded in a single-bond geometry to one Sr(2) and one Sr(3) atom. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a 4-coordinate geometry to two equivalent Sr(1), one Al(1), and one Al(2) atom. The Al(1)-Al(1) bond length is 2.03 Å. The Al(1)-Al(2) bond length is 1.61 Å. In the second Al site, Al(2) is bonded in a 2-coordinate geometry to one Sr(2) and one Al(1) atom.