data_SrNbSi
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.8
_cell_length_b   4.8
_cell_length_c   4.8
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   SrNbSi
_chemical_formula_sum   'Sr1 Nb1 Si1'
_cell_volume   77.97
_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
  Sr  Sr2  1  0.39  0.39  0.39  1.0
  Nb  Nb0  1  0.7  0.7  0.7  1.0
  Si  Si1  1  0.0  0.0  0.0  1.0

data_SrNbSi
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.8
_cell_length_b   4.8
_cell_length_c   11.75
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   SrNbSi
_chemical_formula_sum   'Sr3 Nb3 Si3'
_cell_volume   233.92
_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
  Sr  Sr0  3  0.0  0.0  0.61  1.0
  Nb  Nb1  3  0.0  0.0  0.3  1.0
  Si  Si2  3  0.0  0.0  0.0  1.0

Sr Nb Si
SrNbSi is half-Heusler structured and crystallizes in the trigonal R3m space group. Sr(1) is bonded to four equivalent Nb(1) and three equivalent Si(1) atoms to form distorted SrNb4Si3 hexagonal pyramids that share corners with three equivalent Nb(1)Sr4Si3 hexagonal pyramids, corners with six equivalent Sr(1)Nb4Si3 hexagonal pyramids, edges with three equivalent Nb(1)Sr4Si3 hexagonal pyramids, and edges with six equivalent Sr(1)Nb4Si3 hexagonal pyramids. There are three shorter (2.79 Å) and one longer (3.58 Å) Sr(1)-Nb(1) bond length. All Sr(1)-Si(1) bond lengths are 2.85 Å. Nb(1) is bonded to four equivalent Sr(1) and three equivalent Si(1) atoms to form distorted NbSr4Si3 hexagonal pyramids that share corners with three equivalent Sr(1)Nb4Si3 hexagonal pyramids, corners with six equivalent Nb(1)Sr4Si3 hexagonal pyramids, edges with three equivalent Sr(1)Nb4Si3 hexagonal pyramids, and edges with six equivalent Nb(1)Sr4Si3 hexagonal pyramids. All Nb(1)-Si(1) bond lengths are 2.79 Å. Si(1) is bonded in a hexagonal planar geometry to three equivalent Sr(1) and three equivalent Nb(1) atoms.