data_FeCu3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.79
_cell_length_b   2.79
_cell_length_c   11.16
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   FeCu3
_chemical_formula_sum   'Fe2 Cu6'
_cell_volume   86.87
_cell_formula_units_Z   2
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
  Fe  Fe6  1  0.4  0.0  0.88  1.0
  Fe  Fe7  1  0.0  0.4  0.28  1.0
  Cu  Cu0  1  0.4  0.0  0.67  1.0
  Cu  Cu1  1  0.0  0.4  0.07  1.0
  Cu  Cu2  1  0.4  0.0  0.46  1.0
  Cu  Cu3  1  0.0  0.4  0.7  1.0
  Cu  Cu4  1  0.4  0.0  0.09  1.0
  Cu  Cu5  1  0.0  0.4  0.49  1.0

data_FeCu3
_symmetry_space_group_name_H-M   C2/m
_cell_length_a   3.95
_cell_length_b   3.95
_cell_length_c   11.16
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   12
_chemical_formula_structural   FeCu3
_chemical_formula_sum   'Fe4 Cu12'
_cell_volume   173.74
_cell_formula_units_Z   4
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-x, -y, -z'
  3  '-x, y, -z'
  4  'x, -y, z'
  5  'x+1/2, y+1/2, z'
  6  '-x+1/2, -y+1/2, -z'
  7  '-x+1/2, y+1/2, -z'
  8  '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
  Fe  Fe0  4  0.2  0.5  0.8  1.0
  Cu  Cu1  4  0.2  0.5  0.01  1.0
  Cu  Cu2  4  0.2  0.5  0.38  1.0
  Cu  Cu3  4  0.2  0.5  0.59  1.0

Fe Fe Cu Cu Cu Cu Cu Cu
FeCu3 crystallizes in the monoclinic C2/m space group. Fe(1) is bonded in a 2-coordinate geometry to one Cu(1) and one Cu(2) atom. The Fe(1)-Cu(1) bond length is 2.34 Å. The Fe(1)-Cu(2) bond length is 2.34 Å. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 6-coordinate geometry to one Fe(1) and five equivalent Cu(3) atoms. There are a spread of Cu(1)-Cu(3) bond distances ranging from 1.58-2.40 Å. In the second Cu site, Cu(2) is bonded in a 1-coordinate geometry to one Fe(1) and one Cu(2) atom. The Cu(2)-Cu(2) bond length is 1.58 Å. In the third Cu site, Cu(3) is bonded in a 1-coordinate geometry to five equivalent Cu(1) atoms.