The crystal structure described by Ta3Cu is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to four equivalent Ta(1), four equivalent Ta(2), and four equivalent Cu(1) atoms to form distorted TaTa8Cu4 cuboctahedra that share corners with twelve equivalent Ta(1)Ta8Cu4 cuboctahedra, edges with eight equivalent Ta(1)Ta8Cu4 cuboctahedra, edges with eight equivalent Ta(2)Ta8Cu4 cuboctahedra, edges with eight equivalent Cu(1)Ta12 cuboctahedra, faces with four equivalent Ta(2)Ta8Cu4 cuboctahedra, faces with four equivalent Cu(1)Ta12 cuboctahedra, and faces with ten equivalent Ta(1)Ta8Cu4 cuboctahedra. In the second Ta site, Ta(2) is bonded to eight equivalent Ta(1) and four equivalent Cu(1) atoms to form distorted TaTa8Cu4 cuboctahedra that share corners with four equivalent Ta(2)Ta8Cu4 cuboctahedra, corners with eight equivalent Cu(1)Ta12 cuboctahedra, edges with eight equivalent Ta(2)Ta8Cu4 cuboctahedra, edges with sixteen equivalent Ta(1)Ta8Cu4 cuboctahedra, faces with four equivalent Ta(2)Ta8Cu4 cuboctahedra, faces with six equivalent Cu(1)Ta12 cuboctahedra, and faces with eight equivalent Ta(1)Ta8Cu4 cuboctahedra. Cu(1) is bonded to four equivalent Ta(2) and eight equivalent Ta(1) atoms to form CuTa12 cuboctahedra that share corners with four equivalent Cu(1)Ta12 cuboctahedra, corners with eight equivalent Ta(2)Ta8Cu4 cuboctahedra, edges with eight equivalent Cu(1)Ta12 cuboctahedra, edges with sixteen equivalent Ta(1)Ta8Cu4 cuboctahedra, faces with four equivalent Cu(1)Ta12 cuboctahedra, faces with six equivalent Ta(2)Ta8Cu4 cuboctahedra, and faces with eight equivalent Ta(1)Ta8Cu4 cuboctahedra. is represented by the CIF file [CIF]
data_Ta3Cu
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.076
_cell_length_b   5.076
_cell_length_c   5.076
_cell_angle_alpha   133.427
_cell_angle_beta   133.427
_cell_angle_gamma   67.985
_symmetry_Int_Tables_number   1
_cell_volume   67.770
_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  Ta0  1  0.750  0.250  0.500  1.0
  Ta  Ta1  1  0.250  0.750  0.500  1.0
  Ta  Ta2  1  0.500  0.500  0.000  1.0
  Cu  Cu3  1  0.000  0.000  0.000  1.0
[/CIF]
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The crystal structure described by Ta3Cu is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to four equivalent Ta(1), four equivalent Ta(2), and four equivalent Cu(1) atoms to form distorted TaTa8Cu4 cuboctahedra that share corners with twelve equivalent Ta(1)Ta8Cu4 cuboctahedra, edges with eight equivalent Ta(1)Ta8Cu4 cuboctahedra, edges with eight equivalent Ta(2)Ta8Cu4 cuboctahedra, edges with eight equivalent Cu(1)Ta12 cuboctahedra, faces with four equivalent Ta(2)Ta8Cu4 cuboctahedra, faces with four equivalent Cu(1)Ta12 cuboctahedra, and faces with ten equivalent Ta(1)Ta8Cu4 cuboctahedra. In the second Ta site, Ta(2) is bonded to eight equivalent Ta(1) and four equivalent Cu(1) atoms to form distorted TaTa8Cu4 cuboctahedra that share corners with four equivalent Ta(2)Ta8Cu4 cuboctahedra, corners with eight equivalent Cu(1)Ta12 cuboctahedra, edges with eight equivalent Ta(2)Ta8Cu4 cuboctahedra, edges with sixteen equivalent Ta(1)Ta8Cu4 cuboctahedra, faces with four equivalent Ta(2)Ta8Cu4 cuboctahedra, faces with six equivalent Cu(1)Ta12 cuboctahedra, and faces with eight equivalent Ta(1)Ta8Cu4 cuboctahedra. Cu(1) is bonded to four equivalent Ta(2) and eight equivalent Ta(1) atoms to form CuTa12 cuboctahedra that share corners with four equivalent Cu(1)Ta12 cuboctahedra, corners with eight equivalent Ta(2)Ta8Cu4 cuboctahedra, edges with eight equivalent Cu(1)Ta12 cuboctahedra, edges with sixteen equivalent Ta(1)Ta8Cu4 cuboctahedra, faces with four equivalent Cu(1)Ta12 cuboctahedra, faces with six equivalent Ta(2)Ta8Cu4 cuboctahedra, and faces with eight equivalent Ta(1)Ta8Cu4 cuboctahedra. is represented by the CIF file [CIF]
data_Ta3Cu
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.076
_cell_length_b   5.076
_cell_length_c   5.076
_cell_angle_alpha   133.427
_cell_angle_beta   133.427
_cell_angle_gamma   67.985
_symmetry_Int_Tables_number   1
_cell_volume   67.770
_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  Ta0  1  0.750  0.250  0.500  1.0
  Ta  Ta1  1  0.250  0.750  0.500  1.0
  Ta  Ta2  1  0.500  0.500  0.000  1.0
  Cu  Cu3  1  0.000  0.000  0.000  1.0
[/CIF]
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