data_Be2AlCu
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.68
_cell_length_b   3.26
_cell_length_c   4.98
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Be2AlCu
_chemical_formula_sum   'Be2 Al1 Cu1'
_cell_volume   43.52
_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
  Be  Be1  1  0.34  0.63  0.32  1.0
  Be  Be2  1  0.34  0.63  0.66  1.0
  Al  Al0  1  0.0  0.0  0.0  1.0
  Cu  Cu3  1  0.0  0.0  0.49  1.0

data_Be2AlCu
_symmetry_space_group_name_H-M   Pm
_cell_length_a   2.68
_cell_length_b   4.98
_cell_length_c   3.26
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   6
_chemical_formula_structural   Be2AlCu
_chemical_formula_sum   'Be2 Al1 Cu1'
_cell_volume   43.52
_cell_formula_units_Z   1
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
  Be  Be0  2  0.34  0.32  0.63  1.0
  Al  Al1  1  0.0  0.0  0.0  1.0
  Cu  Cu2  1  0.0  0.5  0.0  1.0

Be Be Al Cu
Be Be Al Cu 0 3 o + o 0 1 o o o 0 2 + + o 0 2 o + o 0 2 o o o 1 3 o + o 1 2 + + + 1 2 o + + 1 2 o o + 2 2 + o o 2 3 o o - 2 3 o o o 
Be2CuAl crystallizes in the triclinic P1 space group. There are two inequivalent Be sites. In the first Be site, Be(1) is bonded in a 1-coordinate geometry to one Cu(1) and three equivalent Al(1) atoms. The Be(1)-Cu(1) bond length is 1.73 Å. There are a spread of Be(1)-Al(1) bond distances ranging from 2.21-2.76 Å. In the second Be site, Be(2) is bonded in a 1-coordinate geometry to one Cu(1) and three equivalent Al(1) atoms. The Be(2)-Cu(1) bond length is 1.73 Å. There are a spread of Be(2)-Al(1) bond distances ranging from 2.29-2.82 Å. Cu(1) is bonded in a 2-coordinate geometry to one Be(1), one Be(2), and two equivalent Al(1) atoms. There is one shorter (2.44 Å) and one longer (2.54 Å) Cu(1)-Al(1) bond length. Al(1) is bonded in a 10-coordinate geometry to three equivalent Be(1), three equivalent Be(2), two equivalent Cu(1), and two equivalent Al(1) atoms. Both Al(1)-Al(1) bond lengths are 2.68 Å.