data_TaBeCu2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.78
_cell_length_b   2.78
_cell_length_c   6.41
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   TaBeCu2
_chemical_formula_sum   'Ta1 Be1 Cu2'
_cell_volume   49.59
_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  Ta3  1  0.0  0.0  0.21  1.0
  Be  Be0  1  0.0  0.0  0.0  1.0
  Cu  Cu1  1  0.39  0.39  0.28  1.0
  Cu  Cu2  1  0.39  0.39  0.14  1.0

data_TaBeCu2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   3.93
_cell_length_b   3.93
_cell_length_c   6.41
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   TaBeCu2
_chemical_formula_sum   'Ta2 Be2 Cu4'
_cell_volume   99.18
_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  0.21  1.0
  Be  Be1  2  0.0  0.0  0.0  1.0
  Cu  Cu2  2  0.39  0.0  0.14  1.0
  Cu  Cu3  2  0.39  0.0  0.28  1.0

Ta Be Cu Cu
BeTaCu2 crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two BeTaCu2 clusters. Be(1) is bonded in a 1-coordinate geometry to one Ta(1) atom. The Be(1)-Ta(1) bond length is 1.33 Å. Ta(1) is bonded in a 3-coordinate geometry to one Be(1), one Cu(1), and one Cu(2) atom. The Ta(1)-Cu(1) bond length is 1.60 Å. The Ta(1)-Cu(2) bond length is 1.60 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a distorted single-bond geometry to one Ta(1) and one Cu(2) atom. The Cu(1)-Cu(2) bond length is 0.88 Å. In the second Cu site, Cu(2) is bonded in a 1-coordinate geometry to one Ta(1) and one Cu(1) atom.