data_Na4YSe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.25
_cell_length_b   6.25
_cell_length_c   6.25
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na4YSe
_chemical_formula_sum   'Na4 Y1 Se1'
_cell_volume   172.4
_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  Na0  1  0.31  0.31  0.53  1.0
  Na  Na1  1  0.31  0.53  0.31  1.0
  Na  Na2  1  0.53  0.31  0.31  1.0
  Na  Na3  1  0.53  0.53  0.53  1.0
  Y  Y5  1  0.21  0.21  0.21  1.0
  Se  Se4  1  0.0  0.0  0.0  1.0

data_Na4YSe
_symmetry_space_group_name_H-M   R3m
_cell_length_a   6.25
_cell_length_b   6.25
_cell_length_c   15.3
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Na4YSe
_chemical_formula_sum   'Na12 Y3 Se3'
_cell_volume   517.21
_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  9  0.07  0.14  0.62  1.0
  Na  Na1  3  0.0  0.0  0.47  1.0
  Y  Y2  3  0.0  0.0  0.79  1.0
  Se  Se3  3  0.0  0.0  0.0  1.0

Na Na Na Na Y Se
Na4YSe crystallizes in the trigonal R3m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 3-coordinate geometry to one Na(2), two equivalent Na(1), two equivalent Y(1), and one Se(1) atom. The Na(1)-Na(2) bond length is 2.33 Å. Both Na(1)-Na(1) bond lengths are 1.34 Å. There is one shorter (2.76 Å) and one longer (3.75 Å) Na(1)-Y(1) bond length. The Na(1)-Se(1) bond length is 2.93 Å. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to three equivalent Na(1) and three equivalent Y(1) atoms. All Na(2)-Y(1) bond lengths are 3.62 Å. Y(1) is bonded in a 10-coordinate geometry to three equivalent Na(2), six equivalent Na(1), and one Se(1) atom. The Y(1)-Se(1) bond length is 3.19 Å. Se(1) is bonded in a distorted tetrahedral geometry to three equivalent Na(1) and one Y(1) atom.