data_NaSm2Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.18
_cell_length_b   5.18
_cell_length_c   5.18
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   NaSm2Si
_chemical_formula_sum   'Na1 Sm2 Si1'
_cell_volume   98.5
_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
  Na  Na0  1  0.0  0.0  0.0  1.0
  Sm  Sm2  1  0.5  0.5  0.5  1.0
  Sm  Sm3  1  0.83  0.83  0.83  1.0
  Si  Si1  1  0.67  0.67  0.67  1.0

data_NaSm2Si
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.18
_cell_length_b   5.18
_cell_length_c   12.7
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   NaSm2Si
_chemical_formula_sum   'Na3 Sm6 Si3'
_cell_volume   295.51
_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
  Sm  Sm1  3  0.0  0.0  0.17  1.0
  Sm  Sm2  3  0.0  0.0  0.5  1.0
  Si  Si3  3  0.0  0.0  0.33  1.0

Na Sm Sm Si
NaSm2Si crystallizes in the trigonal R3m space group. Na(1) is bonded to one Sm(2) and three equivalent Si(1) atoms to form distorted NaSmSi3 trigonal pyramids that share  a cornercorner with one Si(1)Na3Sm2 trigonal bipyramid and corners with six equivalent Na(1)SmSi3 trigonal pyramids. The Na(1)-Sm(2) bond length is 2.12 Å. All Na(1)-Si(1) bond lengths are 2.99 Å. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a single-bond geometry to one Si(1) atom. The Sm(1)-Si(1) bond length is 2.12 Å. In the second Sm site, Sm(2) is bonded in a distorted linear geometry to one Na(1) and one Si(1) atom. The Sm(2)-Si(1) bond length is 2.12 Å. Si(1) is bonded to three equivalent Na(1), one Sm(1), and one Sm(2) atom to form distorted SiNa3Sm2 trigonal bipyramids that share corners with six equivalent Si(1)Na3Sm2 trigonal bipyramids and  a cornercorner with one Na(1)SmSi3 trigonal pyramid.