data_NaCr2Cu
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.56
_cell_length_b   4.56
_cell_length_c   4.56
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   NaCr2Cu
_chemical_formula_sum   'Na1 Cr2 Cu1'
_cell_volume   67.05
_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
  Na  Na3  1  0.0  0.0  0.0  1.0
  Cr  Cr0  1  0.61  0.61  0.61  1.0
  Cr  Cr1  1  0.84  0.84  0.84  1.0
  Cu  Cu2  1  0.22  0.22  0.22  1.0

data_NaCr2Cu
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.56
_cell_length_b   4.56
_cell_length_c   11.17
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   NaCr2Cu
_chemical_formula_sum   'Na3 Cr6 Cu3'
_cell_volume   201.14
_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
  Na  Na0  3  0.0  0.0  0.0  1.0
  Cr  Cr1  3  0.0  0.0  0.16  1.0
  Cr  Cr2  3  0.0  0.0  0.39  1.0
  Cu  Cu3  3  0.0  0.0  0.78  1.0

Na Cr Cr Cu
NaCr2Cu crystallizes in the trigonal R3m space group. Na(1) is bonded in a 1-coordinate geometry to one Cr(2), three equivalent Cr(1), and four equivalent Cu(1) atoms. The Na(1)-Cr(2) bond length is 1.83 Å. All Na(1)-Cr(1) bond lengths are 2.70 Å. There is one shorter (2.51 Å) and three longer (2.90 Å) Na(1)-Cu(1) bond lengths. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded in a 7-coordinate geometry to three equivalent Na(1), one Cr(2), and three equivalent Cu(1) atoms. The Cr(1)-Cr(2) bond length is 2.51 Å. All Cr(1)-Cu(1) bond lengths are 2.70 Å. In the second Cr site, Cr(2) is bonded in a single-bond geometry to one Na(1), one Cr(1), and three equivalent Cu(1) atoms. All Cr(2)-Cu(1) bond lengths are 2.70 Å. Cu(1) is bonded in a distorted single-bond geometry to four equivalent Na(1), three equivalent Cr(1), and three equivalent Cr(2) atoms.