data_global _chemical_name_mineral 'Epididymite-potassian' loop_ _publ_author_name 'Naumova I S' 'Pobedimskaya E A' 'Pushcharovskii D Y' 'Belov N V' 'Altukhova Yu N' _journal_name_full 'Doklady Akademii Nauk SSSR' _journal_volume 229 _journal_year 1976 _journal_page_first 856 _journal_page_last 859 _publ_section_title ; Crystal structure of synthetic K2Be2Si6O15 of the epidimite group Note: c-cell edge altered to reproduce bond lengths ; _database_code_amcsd 0012454 _chemical_compound_source 'Synthetic' _chemical_formula_sum 'K2 Be2 Si6 O15' _cell_length_a 7.485 _cell_length_b 15.453 _cell_length_c 11.418 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 90 _cell_volume 1320.671 _exptl_crystal_density_diffrn 2.538 _symmetry_space_group_name_H-M 'C m c 21' loop_ _space_group_symop_operation_xyz 'x,y,z' '1/2+x,1/2+y,z' 'x,-y,1/2+z' '1/2+x,1/2-y,1/2+z' '-x,y,z' '1/2-x,1/2+y,z' '-x,-y,1/2+z' '1/2-x,1/2-y,1/2+z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_U_iso_or_equiv K1 0.50000 0.28180 0.36190 0.03141 K2 0.50000 0.39870 0.08400 0.01178 Be1 0.14890 0.37980 0.22750 0.00329 Si1 0.21170 0.20950 0.13360 0.00773 Si2 0.20460 0.05560 0.31030 0.00507 Si3 0.00000 0.34970 0.46590 0.00405 Si4 0.00000 0.45450 0.00090 0.00659 O1 0.32200 0.20000 0.01090 0.00849 O2 0.25830 0.12910 0.21640 0.01710 O3 0.32450 0.07640 0.42960 0.01077 O4 0.27010 0.29580 0.19450 0.00912 O5 0.27040 0.46230 0.26310 0.01469 O6 0.00000 0.21600 0.09480 0.02989 O7 0.00000 0.40630 0.12830 0.00861 O8 0.00000 0.07150 0.35180 0.00165 O9 0.00000 0.35420 0.33200 0.00659 O10 0.00000 0.44090 0.52560 0.01203