data_FeCuNi2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.51
_cell_length_b   2.51
_cell_length_c   7.18
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   FeCuNi2
_chemical_formula_sum   'Fe1 Cu1 Ni2'
_cell_volume   45.13
_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
  Fe  Fe1  1  0.0  0.0  0.43  1.0
  Cu  Cu0  1  0.25  0.25  0.55  1.0
  Ni  Ni2  1  0.25  0.25  0.02  1.0
  Ni  Ni3  1  0.0  0.0  0.76  1.0

data_FeCuNi2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   3.55
_cell_length_b   3.55
_cell_length_c   7.18
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   FeCuNi2
_chemical_formula_sum   'Fe2 Cu2 Ni4'
_cell_volume   90.26
_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
  Fe  Fe0  2  0.0  0.0  0.43  1.0
  Cu  Cu1  2  0.25  0.0  0.55  1.0
  Ni  Ni2  2  0.0  0.0  0.76  1.0
  Ni  Ni3  2  0.25  0.0  0.02  1.0

Fe Cu Ni Ni
Fe Cu Ni Ni 0 1 o o o 1 3 o o o 2 3 o o - 2 3 o + - 2 3 + o - 2 2 + o o 2 2 o + o 
CuFeNi2 crystallizes in the monoclinic Cm space group. Fe(1) is bonded in a single-bond geometry to one Ni(1) and one Cu(1) atom. The Fe(1)-Ni(1) bond length is 3.11 Å. The Fe(1)-Cu(1) bond length is 1.24 Å. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 8-coordinate geometry to one Fe(1), three equivalent Ni(2), and four equivalent Ni(1) atoms. There is one shorter (2.08 Å) and two longer (2.72 Å) Ni(1)-Ni(2) bond lengths. All Ni(1)-Ni(1) bond lengths are 2.51 Å. In the second Ni site, Ni(2) is bonded in a 2-coordinate geometry to three equivalent Ni(1) and one Cu(1) atom. The Ni(2)-Cu(1) bond length is 1.73 Å. Cu(1) is bonded in a distorted single-bond geometry to one Fe(1) and one Ni(2) atom.