data_global _chemical_name_mineral 'Richterite' loop_ _publ_author_name 'Robert J-L' 'Della Ventura G' 'Raudsepp M' 'Hawthorne F C' _journal_name_full 'European Journal of Mineralogy' _journal_volume 5 _journal_year 1993 _journal_page_first 199 _journal_page_last 206 _publ_section_title ; Rietveld structure refinement of synthetic strontium-rich potassium-richterites Sample: KSr_50 ; _database_code_amcsd 0006476 _chemical_formula_sum 'K Mg5 (Na Ca.5 Sr.5) Si8 O24 H2' _cell_length_a 10.1063 _cell_length_b 18.056 _cell_length_c 5.2717 _cell_angle_alpha 90 _cell_angle_beta 105.168 _cell_angle_gamma 90 _cell_volume 928.464 _exptl_crystal_density_diffrn 3.070 _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_occupancy _atom_site_U_iso_or_equiv KA 0.01830 0.50000 0.03040 0.50000 0.02913 MgM1 0.00000 0.09000 0.50000 1.00000 0.00760 MgM2 0.00000 0.18080 0.00000 1.00000 0.00760 MgM3 0.00000 0.00000 0.00000 1.00000 0.00760 NaM4 0.00000 0.27780 0.50000 0.50000 0.01140 CaM4 0.00000 0.27780 0.50000 0.25000 0.01140 SrM4 0.00000 0.27780 0.50000 0.25000 0.00507 SiT1 0.27350 0.08540 0.30460 1.00000 0.00507 SiT2 0.28420 0.17080 0.80420 1.00000 0.01013 O1 0.10260 0.08880 0.21430 1.00000 0.01013 O2 0.11500 0.17050 0.72150 1.00000 0.01013 O-H3 0.10610 0.00000 0.72910 1.00000 0.01013 O4 0.35380 0.24790 0.80080 1.00000 0.01393 O5 0.33810 0.12980 0.09990 1.00000 0.01393 O6 0.33460 0.11370 0.59630 1.00000 0.01520 O7 0.32750 0.00000 0.29980 1.00000 ?