data_global
_chemical_name_mineral 'Helium'
loop_
_publ_author_name
'Schuch A F'
'Grilly E R'
'Mills R L'
_journal_name_full 'Physical Review'
_journal_volume 110 
_journal_year 1958
_journal_page_first 775
_journal_page_last 775
_publ_section_title
;
 Structure of the alpha and beta forms of solid He
 Sample: at T = 3.3 K & P = .018 GPa
 Note: structure known as the beta form
;
_database_code_amcsd 0015154
_chemical_compound_source 'Synthetic'
_chemical_formula_sum 'He'
_cell_length_a 3.46
_cell_length_b 3.46
_cell_length_c 5.60
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 58.059
_exptl_crystal_density_diffrn      0.229
_symmetry_space_group_name_H-M 'P 63/m m c'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '-x,-x+y,1/2+z'
  'x,x-y,1/2-z'
  '-x+y,-x,1/2-z'
  'x-y,x,1/2+z'
  '-y,-x,z'
  'y,x,-z'
  'y,-x+y,-z'
  '-y,x-y,z'
  'x-y,-y,1/2+z'
  '-x+y,y,1/2-z'
  'x,y,1/2-z'
  '-x,-y,1/2+z'
  'x,x-y,z'
  '-x,-x+y,-z'
  'x-y,x,-z'
  '-x+y,-x,z'
  'y,x,1/2+z'
  '-y,-x,1/2-z'
  '-y,x-y,1/2-z'
  'y,-x+y,1/2+z'
  '-x+y,y,z'
  'x-y,-y,-z'
  '-x,-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
He   0.33333   0.66667   0.25000