data_[He2]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  He  4.16  1.4  0.0000
]
_symmetry_space_group_name_H-M [P6_3/mmc]
_cell_length_a [2.7327]
_cell_length_b [2.7327]
_cell_length_c [4.4493]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [120.0000]
_symmetry_Int_Tables_number [194]
_chemical_formula_structural [He]
_chemical_formula_sum '[He2]'
_cell_volume [28.7742]
_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
[
  He  He0  2  0.3333  0.6667  0.2500  1
]