data_NdEr2Cu
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.24
_cell_length_b   5.24
_cell_length_c   5.24
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   NdEr2Cu
_chemical_formula_sum   'Nd1 Er2 Cu1'
_cell_volume   101.5
_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
  Nd  Nd3  1  0.7  0.7  0.7  1.0
  Er  Er1  1  0.55  0.55  0.55  1.0
  Er  Er2  1  0.85  0.85  0.85  1.0
  Cu  Cu0  1  0.0  0.0  0.0  1.0

data_NdEr2Cu
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.24
_cell_length_b   5.24
_cell_length_c   12.83
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   NdEr2Cu
_chemical_formula_sum   'Nd3 Er6 Cu3'
_cell_volume   304.5
_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
  Nd  Nd0  3  0.0  0.0  0.3  1.0
  Er  Er1  3  0.0  0.0  0.15  1.0
  Er  Er2  3  0.0  0.0  0.45  1.0
  Cu  Cu3  3  0.0  0.0  0.0  1.0

Nd Er Er Cu
Nd Er Er Cu 0 1 o o o 0 2 o o o 2 3 + + + 
Er2NdCu crystallizes in the trigonal R3m space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a single-bond geometry to one Nd(1) atom. The Er(1)-Nd(1) bond length is 1.91 Å. In the second Er site, Er(2) is bonded in a linear geometry to one Nd(1) and one Cu(1) atom. The Er(2)-Nd(1) bond length is 1.91 Å. The Er(2)-Cu(1) bond length is 1.91 Å. Nd(1) is bonded to one Er(1), one Er(2), and three equivalent Cu(1) atoms to form distorted corner-sharing NdEr2Cu3 trigonal bipyramids. All Nd(1)-Cu(1) bond lengths are 3.06 Å. Cu(1) is bonded in a distorted single-bond geometry to one Er(2) and three equivalent Nd(1) atoms.