data_global _chemical_name_mineral 'Fluorine' loop_ _publ_author_name 'Meyer L' 'Barrett C S' 'Greer S C' _journal_name_full 'Journal of Chemical Physics' _journal_volume 49 _journal_year 1968 _journal_page_first 1902 _journal_page_last 1907 _publ_section_title ; Crystal structure of alpha-fluorine Sample: at T = 23 K Note: alpha phase, stable between T = 0 K & 45.6 K ; _database_code_amcsd 0012990 _chemical_compound_source 'Synthetic' _chemical_formula_sum 'F' _cell_length_a 5.50 _cell_length_b 3.28 _cell_length_c 10.01 _cell_angle_alpha 90 _cell_angle_beta 134.66 _cell_angle_gamma 90 _cell_volume 128.445 _exptl_crystal_density_diffrn 1.965 _symmetry_space_group_name_H-M 'C 1 2/m 1' loop_ _space_group_symop_operation_xyz 'x,y,z' '1/2+x,1/2+y,z' 'x,-y,z' '1/2+x,1/2-y,z' '-x,y,-z' '1/2-x,1/2+y,-z' '-x,-y,-z' '1/2-x,1/2-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_U_iso_or_equiv F1 0.15000 0.00000 0.09960 0.07599 F2 0.10500 0.00000 0.60000 0.07599