data_global
_chemical_name_mineral 'Selenium'
loop_
_publ_author_name
'Keller R'
'Holzapfel W B'
'Schulz H'
_journal_name_full 'Physical Review'
_journal_volume B16 
_journal_year 1977
_journal_page_first 4404
_journal_page_last 4412
_publ_section_title
;
 Effect of pressure on the atom positions in Se and Te
 Note: known as alpha phase with trigonal structure
;
_database_code_amcsd 0015161
_chemical_compound_source 'Synthetic'
_chemical_formula_sum 'Se'
_cell_length_a 4.368
_cell_length_b 4.368
_cell_length_c 4.958
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 81.922
_exptl_crystal_density_diffrn      4.801
_symmetry_space_group_name_H-M 'P 31 2 1'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  'y,x,-z'
  '-y,x-y,1/3+z'
  '-x,-x+y,1/3-z'
  '-x+y,-x,2/3+z'
  'x-y,-y,2/3-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
Se   0.22540   0.00000   0.33333