data_[Rb4Mg2Be4Se8]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Rb  0.8200  2.3500  1.6600
  Mg  1.3100  1.5000  0.8600
  Be  1.5700  1.0500  0.5900
  Se  2.5500  1.1500  1.0133
]
_symmetry_space_group_name_H-M [C2/m]
_cell_length_a [15.2554]
_cell_length_b [3.8712]
_cell_length_c [7.9298]
_cell_angle_alpha [90.0000]
_cell_angle_beta [108.4892]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [12]
_chemical_formula_structural [Rb2Mg(BeSe2)2]
_chemical_formula_sum '[Rb4 Mg2 Be4 Se8]'
_cell_volume [444.1289]
_cell_formula_units_Z [2]
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
[
  Rb  Rb0  4  0.1272  0.0000  0.5337  1
  Mg  Mg1  2  0.0000  0.0000  0.0000  1
  Be  Be2  4  0.1751  0.5000  0.9761  1
  Se  Se3  4  0.0319  0.5000  0.7908  1
  Se  Se4  4  0.2069  0.0000  0.1520  1
]