data_Ta2BeCu
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.13
_cell_length_b   9.13
_cell_length_c   9.13
_cell_angle_alpha   17.6
_cell_angle_beta   17.6
_cell_angle_gamma   17.6
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ta2BeCu
_chemical_formula_sum   'Ta2 Be1 Cu1'
_cell_volume   60.75
_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
  Ta  Ta2  1  0.0  0.0  0.81  1.0
  Ta  Ta3  1  0.0  0.0  0.16  1.0
  Be  Be0  1  0.0  0.0  0.0  1.0
  Cu  Cu1  1  0.0  0.0  0.48  1.0

data_Ta2BeCu
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.84
_cell_length_b   2.79
_cell_length_c   9.13
_cell_angle_alpha   90.0
_cell_angle_beta   100.17
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Ta2BeCu
_chemical_formula_sum   'Ta4 Be2 Cu2'
_cell_volume   121.5
_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
  Ta  Ta0  2  -0.0  0.0  0.84  1.0
  Ta  Ta1  2  -0.0  0.0  0.19  1.0
  Be  Be2  2  0.0  0.0  0.0  1.0
  Cu  Cu3  2  -0.0  0.0  0.52  1.0

Ta Ta Be Cu
BeTa2Cu crystallizes in the monoclinic Cm space group. Be(1) is bonded in a linear geometry to one Ta(1) and one Ta(2) atom. The Be(1)-Ta(1) bond length is 1.74 Å. The Be(1)-Ta(2) bond length is 1.43 Å. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a distorted single-bond geometry to one Be(1) and one Cu(1) atom. The Ta(1)-Cu(1) bond length is 2.98 Å. In the second Ta site, Ta(2) is bonded in a distorted single-bond geometry to one Be(1) and one Cu(1) atom. The Ta(2)-Cu(1) bond length is 2.98 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one Ta(1); one Ta(2); and six Cu(1,1) atoms to form a mixture of distorted corner and edge-sharing CuTa2Cu6 hexagonal bipyramids. All Cu(1)-Cu(1,1) bond lengths are 2.79 Å. In the second Cu site, Cu(1) is bonded to one Ta(1); one Ta(2); and six Cu(1,1) atoms to form a mixture of distorted corner and edge-sharing CuTa2Cu6 hexagonal bipyramids. The Cu(1)-Ta(1) bond length is 2.98 Å. The Cu(1)-Ta(2) bond length is 2.98 Å. Both Cu(1)-Cu(1) bond lengths are 2.79 Å.