data_global _chemical_name_mineral 'Selenium' loop_ _publ_author_name 'Foss O' 'Janickis V' _journal_name_full 'Dalton Transactions' _journal_volume 1980 _journal_year 1980 _journal_page_first 624 _journal_page_last 627 _publ_section_title ; Crystal structure of gamma-monoclinic selenium Note: structure known as gamma phase Note: gamma-monoclinic selenium is allotrope of cyclo-octaselenium ; _database_code_amcsd 0012427 _chemical_compound_source 'Synthetic' _chemical_formula_sum 'Se' _cell_length_a 15.018 _cell_length_b 14.713 _cell_length_c 8.789 _cell_angle_alpha 90 _cell_angle_beta 93.61 _cell_angle_gamma 90 _cell_volume 1938.162 _exptl_crystal_density_diffrn 4.330 _symmetry_space_group_name_H-M 'P 1 21/c 1' loop_ _space_group_symop_operation_xyz 'x,y,z' 'x,1/2-y,1/2+z' '-x,1/2+y,1/2-z' '-x,-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z Se1 0.18313 0.14063 0.03451 Se2 0.22856 0.28408 0.12262 Se3 0.35548 0.31907 -0.00548 Se4 0.47826 0.28776 0.16131 Se5 0.52853 0.14438 0.09345 Se6 0.47966 0.04033 0.27102 Se7 0.36296 -0.02818 0.15123 Se8 0.22521 0.04261 0.23430 Se9 0.09552 0.48601 0.14213 Se10 0.01298 0.58883 0.27815 Se11 -0.01931 0.71476 0.12135 Se12 0.08347 0.82945 0.18553 Se13 0.19177 0.81338 0.00963 Se14 0.31020 0.73961 0.14402 Se15 0.30834 0.59137 0.04778 Se16 0.24353 0.50553 0.23353