data_global _chemical_name_mineral 'Selenium' loop_ _publ_author_name 'Cherin P' 'Unger P' _journal_name_full 'Inorganic Chemistry' _journal_volume 6 _journal_year 1967 _journal_page_first 1589 _journal_page_last 1591 _publ_section_title ; The crystal structure of trigonal selenium ; _database_code_amcsd 0012674 _chemical_compound_source 'Synthetic' _chemical_formula_sum 'Se' _cell_length_a 4.3662 _cell_length_b 4.3662 _cell_length_c 4.9536 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 81.782 _exptl_crystal_density_diffrn 4.810 _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 loop_ _atom_site_aniso_label _atom_site_aniso_U_11 _atom_site_aniso_U_22 _atom_site_aniso_U_33 _atom_site_aniso_U_12 _atom_site_aniso_U_13 _atom_site_aniso_U_23 Se 0.02448 0.03020 0.04693 0.01510 0.00000 0.00000