data_Ga2SnSe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.02
_cell_length_b   5.02
_cell_length_c   5.02
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ga2SnSe
_chemical_formula_sum   'Ga2 Sn1 Se1'
_cell_volume   89.4
_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
  Ga  Ga0  1  0.32  0.32  0.32  1.0
  Ga  Ga1  1  0.77  0.77  0.77  1.0
  Sn  Sn3  1  0.55  0.55  0.55  1.0
  Se  Se2  1  0.0  0.0  0.0  1.0

data_Ga2SnSe
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.02
_cell_length_b   5.02
_cell_length_c   12.29
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Ga2SnSe
_chemical_formula_sum   'Ga6 Sn3 Se3'
_cell_volume   268.21
_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
  Ga  Ga0  3  0.0  0.0  0.23  1.0
  Ga  Ga1  3  0.0  0.0  0.68  1.0
  Sn  Sn2  3  0.0  0.0  0.45  1.0
  Se  Se3  3  0.0  0.0  0.0  1.0

Ga Ga Sn Se
Ga2SnSe is Heusler structured and crystallizes in the trigonal R3m space group. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded in a 7-coordinate geometry to four equivalent Sn(1) and three equivalent Se(1) atoms. There is one shorter (2.77 Å) and three longer (3.19 Å) Ga(1)-Sn(1) bond lengths. All Ga(1)-Se(1) bond lengths are 2.90 Å. In the second Ga site, Ga(2) is bonded in a 2-coordinate geometry to four equivalent Sn(1) and one Se(1) atom. There is one shorter (2.77 Å) and three longer (3.19 Å) Ga(2)-Sn(1) bond lengths. The Ga(2)-Se(1) bond length is 2.77 Å. Sn(1) is bonded in a 11-coordinate geometry to four equivalent Ga(1), four equivalent Ga(2), and three equivalent Se(1) atoms. All Sn(1)-Se(1) bond lengths are 3.24 Å. Se(1) is bonded to one Ga(2), three equivalent Ga(1), and three equivalent Sn(1) atoms to form distorted edge-sharing SeGa4Sn3 trigonal pyramids.