data_MgSnSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.05
_cell_length_b   5.05
_cell_length_c   3.57
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MgSnSe2
_chemical_formula_sum   'Mg1 Sn1 Se2'
_cell_volume   90.98
_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
  Mg  Mg0  1  0.0  0.0  0.0  1.0
  Sn  Sn3  1  0.52  0.52  0.0  1.0
  Se  Se1  1  0.0  0.52  0.78  1.0
  Se  Se2  1  0.52  0.0  0.78  1.0

data_MgSnSe2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   7.14
_cell_length_b   7.14
_cell_length_c   3.57
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   MgSnSe2
_chemical_formula_sum   'Mg2 Sn2 Se4'
_cell_volume   181.95
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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
  Mg  Mg0  2  0.0  0.0  0.0  1.0
  Sn  Sn1  2  0.02  0.5  -0.0  1.0
  Se  Se2  4  0.26  0.26  0.78  1.0

Mg Sn Se Se
Mg Sn Se Se 0 3 - o - 0 3 o o - 0 2 o - - 0 2 o o - 1 2 o o - 1 2 + o - 1 3 o o - 1 3 o + - 