data_NaCuSn2
_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   NaCuSn2
_chemical_formula_sum   'Na1 Cu1 Sn2'
_cell_volume   91.85
_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  Na1  1  0.0  0.0  0.0  1.0
  Cu  Cu0  1  0.79  0.79  0.79  1.0
  Sn  Sn2  1  0.37  0.37  0.37  1.0
  Sn  Sn3  1  0.58  0.58  0.58  1.0

data_NaCuSn2
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.06
_cell_length_b   5.06
_cell_length_c   12.41
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   NaCuSn2
_chemical_formula_sum   'Na3 Cu3 Sn6'
_cell_volume   275.55
_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
  Cu  Cu1  3  0.0  0.0  0.21  1.0
  Sn  Sn2  3  0.0  0.0  0.42  1.0
  Sn  Sn3  3  0.0  0.0  0.63  1.0

Na Cu Sn Sn
Na Cu Sn Sn 0 1 - - - 0 1 - - o 0 1 o - - 0 1 - o - 0 3 - - o 0 3 - o - 0 3 o - - 0 2 - o o 0 2 o - o 0 2 o o - 1 3 o o o 1 3 o o + 1 3 + o o 1 3 o + o 1 2 o o + 1 2 o + o 1 2 + o o 2 3 o - o 2 3 - o o 2 3 o o - 2 3 o o o 
NaCuSn2 crystallizes in the trigonal R3m space group. Na(1) is bonded in a 10-coordinate geometry to four equivalent Cu(1), three equivalent Sn(1), and three equivalent Sn(2) atoms. There is one shorter (2.60 Å) and three longer (3.30 Å) Na(1)-Cu(1) bond lengths. All Na(1)-Sn(1) bond lengths are 2.96 Å. All Na(1)-Sn(2) bond lengths are 3.11 Å. Cu(1) is bonded in a 1-coordinate geometry to four equivalent Na(1) and one Sn(2) atom. The Cu(1)-Sn(2) bond length is 2.60 Å. There are two inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a 3-coordinate geometry to three equivalent Na(1) and one Sn(2) atom. The Sn(1)-Sn(2) bond length is 2.60 Å. In the second Sn site, Sn(2) is bonded in a 5-coordinate geometry to three equivalent Na(1), one Cu(1), and one Sn(1) atom.