data_Be2AlTl
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.48
_cell_length_b   4.48
_cell_length_c   4.48
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Be2AlTl
_chemical_formula_sum   'Be2 Al1 Tl1'
_cell_volume   63.77
_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  0.59  0.59  0.59  1.0
  Be  Be2  1  0.76  0.76  0.76  1.0
  Al  Al0  1  0.0  0.0  0.0  1.0
  Tl  Tl3  1  0.17  0.17  0.17  1.0

data_Be2AlTl
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.48
_cell_length_b   4.48
_cell_length_c   10.98
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Be2AlTl
_chemical_formula_sum   'Be6 Al3 Tl3'
_cell_volume   191.31
_cell_formula_units_Z   3
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-y, x-y, z'
  3  '-x+y, -x, z'
  4  '-y, -x, z'
  5  '-x+y, y, z'
  6  'x, x-y, z'
  7  'x+1/3, y+2/3, z+2/3'
  8  '-y+1/3, x-y+2/3, z+2/3'
  9  '-x+y+1/3, -x+2/3, z+2/3'
  10  '-y+1/3, -x+2/3, z+2/3'
  11  '-x+y+1/3, y+2/3, z+2/3'
  12  'x+1/3, x-y+2/3, z+2/3'
  13  'x+2/3, y+1/3, z+1/3'
  14  '-y+2/3, x-y+1/3, z+1/3'
  15  '-x+y+2/3, -x+1/3, z+1/3'
  16  '-y+2/3, -x+1/3, z+1/3'
  17  '-x+y+2/3, y+1/3, z+1/3'
  18  'x+2/3, x-y+1/3, z+1/3'
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  3  0.0  0.0  0.24  1.0
  Be  Be1  3  0.0  0.0  0.41  1.0
  Al  Al2  3  0.0  0.0  0.0  1.0
  Tl  Tl3  3  0.0  0.0  0.83  1.0

Be Be Al Tl
Be2TlAl crystallizes in the trigonal R3m space group. There are two inequivalent Be sites. In the first Be site, Be(1) is bonded in a 7-coordinate geometry to one Be(2), three equivalent Tl(1), and three equivalent Al(1) atoms. The Be(1)-Be(2) bond length is 1.88 Å. All Be(1)-Tl(1) bond lengths are 2.74 Å. All Be(1)-Al(1) bond lengths are 2.74 Å. In the second Be site, Be(2) is bonded in a 8-coordinate geometry to one Be(1), three equivalent Tl(1), and four equivalent Al(1) atoms. All Be(2)-Tl(1) bond lengths are 2.74 Å. There is one shorter (2.67 Å) and three longer (2.77 Å) Be(2)-Al(1) bond lengths. Tl(1) is bonded in a distorted single-bond geometry to three equivalent Be(1), three equivalent Be(2), and one Al(1) atom. The Tl(1)-Al(1) bond length is 1.88 Å. Al(1) is bonded in a distorted single-bond geometry to three equivalent Be(1), four equivalent Be(2), and one Tl(1) atom.