data_GaSnSe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.92
_cell_length_b   4.92
_cell_length_c   4.92
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   GaSnSe
_chemical_formula_sum   'Ga1 Sn1 Se1'
_cell_volume   84.0
_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
  Ga  Ga0  1  0.0  0.0  0.0  1.0
  Sn  Sn2  1  0.74  0.74  0.74  1.0
  Se  Se1  1  0.48  0.48  0.48  1.0

data_GaSnSe
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.92
_cell_length_b   4.92
_cell_length_c   12.04
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   GaSnSe
_chemical_formula_sum   'Ga3 Sn3 Se3'
_cell_volume   252.01
_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
  Ga  Ga0  3  0.0  0.0  0.0  1.0
  Sn  Sn1  3  0.0  0.0  0.26  1.0
  Se  Se2  3  0.0  0.0  0.52  1.0

Ga Sn Se
Ga Sn Se 0 2 - - o 0 2 - o - 0 2 - o o 0 2 o - - 0 2 o - o 0 2 o o - 0 1 - - - 0 1 - - o 0 1 - o - 0 1 o - - 1 2 o o o 1 2 o o + 1 2 o + o 1 2 + o o 
GaSnSe is half-Heusler structured and crystallizes in the trigonal R3m space group. Ga(1) is bonded to four equivalent Sn(1) atoms to form GaSn4 tetrahedra that share corners with four equivalent Se(1)Sn4 tetrahedra, corners with twelve equivalent Ga(1)Sn4 tetrahedra, and edges with six equivalent Se(1)Sn4 tetrahedra. There are three shorter (2.97 Å) and one longer (3.15 Å) Ga(1)-Sn(1) bond length. Sn(1) is bonded in a body-centered cubic geometry to four equivalent Ga(1) and four equivalent Se(1) atoms. There are three shorter (2.97 Å) and one longer (3.15 Å) Sn(1)-Se(1) bond length. Se(1) is bonded to four equivalent Sn(1) atoms to form SeSn4 tetrahedra that share corners with four equivalent Ga(1)Sn4 tetrahedra, corners with twelve equivalent Se(1)Sn4 tetrahedra, and edges with six equivalent Ga(1)Sn4 tetrahedra.