data_[Mg3Cr6Sn3Se18]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Mg  1.3100  1.5000  0.8600
  Cr  1.6600  1.4000  0.9400
  Sn  1.9600  1.4500  0.8300
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [R3]
_cell_length_a [6.6363]
_cell_length_b [6.6363]
_cell_length_c [17.7290]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [120.0000]
_symmetry_Int_Tables_number [146]
_chemical_formula_structural [MgCr2SnSe6]
_chemical_formula_sum '[Mg3 Cr6 Sn3 Se18]'
_cell_volume [676.1873]
_cell_formula_units_Z [3]
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  3  0.0000  0.0000  0.3090  1.0
  Cr  Cr1  3  0.0000  0.0000  0.0135  1.0
  Cr  Cr2  3  0.0000  0.0000  0.5141  1.0
  Sn  Sn3  3  0.0000  0.0000  0.8147  1.0
  Se  Se4  9  0.0432  0.3471  0.5862  1.0
  Se  Se5  9  0.0483  0.6923  0.0839  1.0
]