data_global _chemical_name_mineral 'Aphthitalite' loop_ _publ_author_name 'Okada K' 'Ossaka J' _journal_name_full 'Acta Crystallographica, Section B' _journal_volume 36 _journal_year 1980 _journal_page_first 919 _journal_page_last 921 _publ_section_title ; Structures of potassium sodium sulphate and tripotassium sodium disulphate ; _database_code_amcsd 0009708 _chemical_formula_sum 'K3 Na S2 O8' _cell_length_a 5.6801 _cell_length_b 5.6801 _cell_length_c 7.309 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 204.221 _exptl_crystal_density_diffrn 2.703 _symmetry_space_group_name_H-M 'P -3 m 1' loop_ _space_group_symop_operation_xyz 'x,y,z' '-y,-x,z' 'y,-x+y,-z' '-x,-x+y,-z' '-x+y,-x,z' '-x+y,y,z' '-x,-y,-z' 'y,x,-z' '-y,x-y,z' 'x,x-y,z' 'x-y,x,-z' 'x-y,-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z K1 0.00000 0.00000 0.00000 Na2 0.00000 0.00000 0.50000 K3 0.66667 0.33333 0.68310 S 0.66667 0.33333 0.23380 O1 0.66667 0.33333 0.03160 O2 0.80730 -0.80730 0.30180