data_Er2NbCr
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.06
_cell_length_b   5.06
_cell_length_c   5.06
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Er2NbCr
_chemical_formula_sum   'Er2 Nb1 Cr1'
_cell_volume   91.34
_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
  Er  Er1  1  0.36  0.36  0.36  1.0
  Er  Er2  1  0.79  0.79  0.79  1.0
  Nb  Nb3  1  0.57  0.57  0.57  1.0
  Cr  Cr0  1  0.0  0.0  0.0  1.0

data_Er2NbCr
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.06
_cell_length_b   5.06
_cell_length_c   12.38
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Er2NbCr
_chemical_formula_sum   'Er6 Nb3 Cr3'
_cell_volume   274.03
_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
  Er  Er0  3  0.0  0.0  0.21  1.0
  Er  Er1  3  0.0  0.0  0.64  1.0
  Nb  Nb2  3  0.0  0.0  0.43  1.0
  Cr  Cr3  3  0.0  0.0  0.0  1.0

Er Er Nb Cr
Er Er Nb Cr 0 2 o - o 0 2 - o o 0 2 o o - 0 2 o o o 0 3 o o + 0 3 o + o 0 3 + o o 0 1 - o o 0 1 o - o 0 1 o o - 1 3 + o + 1 3 o + + 1 3 + + o 1 3 + + + 1 2 o o o 1 2 o o + 1 2 + o o 1 2 o + o 2 3 o + + 2 3 + o + 2 3 + + o 
Er2NbCr is Heusler structured and crystallizes in the trigonal R3m space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 4-coordinate geometry to one Nb(1) and three equivalent Cr(1) atoms. The Er(1)-Nb(1) bond length is 2.63 Å. All Er(1)-Cr(1) bond lengths are 2.94 Å. In the second Er site, Er(2) is bonded in a distorted linear geometry to one Nb(1) and four equivalent Cr(1) atoms. The Er(2)-Nb(1) bond length is 2.63 Å. There is one shorter (2.63 Å) and three longer (3.28 Å) Er(2)-Cr(1) bond lengths. Nb(1) is bonded in a distorted linear geometry to one Er(1), one Er(2), and three equivalent Cr(1) atoms. All Nb(1)-Cr(1) bond lengths are 3.13 Å. Cr(1) is bonded in a 10-coordinate geometry to three equivalent Er(1), four equivalent Er(2), and three equivalent Nb(1) atoms.