data_BeFeCu
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.65
_cell_length_b   3.65
_cell_length_c   3.65
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   BeFeCu
_chemical_formula_sum   'Be1 Fe1 Cu1'
_cell_volume   34.48
_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
  Be  Be0  1  0.0  0.0  0.0  1.0
  Fe  Fe2  1  0.87  0.87  0.87  1.0
  Cu  Cu1  1  0.29  0.29  0.29  1.0

data_BeFeCu
_symmetry_space_group_name_H-M   R3m
_cell_length_a   3.65
_cell_length_b   3.65
_cell_length_c   8.95
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   BeFeCu
_chemical_formula_sum   'Be3 Fe3 Cu3'
_cell_volume   103.44
_cell_formula_units_Z   3
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-y, x-y, z'
  3  '-x+y, -x, z'
  4  '-y, -x, z'
  5  '-x+y, y, z'
  6  'x, x-y, z'
  7  'x+1/3, y+2/3, z+2/3'
  8  '-y+1/3, x-y+2/3, z+2/3'
  9  '-x+y+1/3, -x+2/3, z+2/3'
  10  '-y+1/3, -x+2/3, z+2/3'
  11  '-x+y+1/3, y+2/3, z+2/3'
  12  'x+1/3, x-y+2/3, z+2/3'
  13  'x+2/3, y+1/3, z+1/3'
  14  '-y+2/3, x-y+1/3, z+1/3'
  15  '-x+y+2/3, -x+1/3, z+1/3'
  16  '-y+2/3, -x+1/3, z+1/3'
  17  '-x+y+2/3, y+1/3, z+1/3'
  18  'x+2/3, x-y+1/3, z+1/3'
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
  Be  Be0  3  0.0  0.0  0.0  1.0
  Fe  Fe1  3  0.0  0.0  0.13  1.0
  Cu  Cu2  3  0.0  0.0  0.71  1.0

Be Fe Cu
Be Fe Cu 0 1 - - - 0 2 o o - 0 2 o - o 0 2 - o o 1 2 + + o 1 2 + o + 1 2 o + + 
BeFeCu is half-Heusler structured and crystallizes in the trigonal R3m space group. Be(1) is bonded in a single-bond geometry to one Fe(1) and four equivalent Cu(1) atoms. The Be(1)-Fe(1) bond length is 1.12 Å. There are three shorter (2.14 Å) and one longer (2.61 Å) Be(1)-Cu(1) bond length. Fe(1) is bonded in a single-bond geometry to one Be(1) and three equivalent Cu(1) atoms. All Fe(1)-Cu(1) bond lengths are 2.24 Å. Cu(1) is bonded in a 7-coordinate geometry to four equivalent Be(1) and three equivalent Fe(1) atoms.