data_global _amcsd_formula_title 'Na1.55K.45Si2O5' loop_ _publ_author_name 'Rakic S' 'Kahlenberg V' _journal_name_full 'European Journal of Mineralogy' _journal_volume 13 _journal_year 2001 _journal_page_first 1215 _journal_page_last 1221 _publ_section_title ; The crystal structure of a mixed alkali phyllosilicate with composition Na1.55K0.45Si2O5 ; _database_code_amcsd 0006920 _chemical_formula_sum 'Na1.55 K.45 Si2 O5' _cell_length_a 4.845 _cell_length_b 8.647 _cell_length_c 11.992 _cell_angle_alpha 90 _cell_angle_beta 90.31 _cell_angle_gamma 90 _cell_volume 502.394 _exptl_crystal_density_diffrn 2.504 _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 _atom_site_occupancy _atom_site_U_iso_or_equiv NaM1 0.74740 0.85940 -0.53690 0.55000 0.02270 KM1 0.74740 0.85940 -0.53690 0.45000 0.02270 NaM2 0.75310 0.39910 -0.44860 1.00000 0.02370 Si1 0.80160 0.32550 -0.17480 1.00000 0.01630 Si2 0.29760 0.47580 -0.28400 1.00000 0.01470 O1 0.24080 0.42210 -0.40890 1.00000 0.03130 O2 0.73130 0.33050 -0.04610 1.00000 0.02300 O3 0.23810 0.65950 -0.26140 1.00000 0.02500 O4 0.62510 0.45030 -0.25030 1.00000 0.02700 O5 0.12270 0.37890 -0.18950 1.00000 0.02630 loop_ _atom_site_aniso_label _atom_site_aniso_U_11 _atom_site_aniso_U_22 _atom_site_aniso_U_33 _atom_site_aniso_U_12 _atom_site_aniso_U_13 _atom_site_aniso_U_23 NaM1 0.01900 0.02300 0.02600 0.00000 -0.00400 -0.00100 KM1 0.01900 0.02300 0.02600 0.00000 -0.00400 -0.00100 NaM2 0.01500 0.03100 0.02500 -0.00300 0.00200 -0.00500 Si1 0.01300 0.01900 0.01700 -0.00100 0.00100 0.00100 Si2 0.01100 0.01700 0.01600 0.00100 0.00300 0.00100 O1 0.02200 0.04600 0.02600 0.00800 -0.00300 -0.00200 O2 0.01800 0.02600 0.02500 -0.00300 0.00600 0.00600 O3 0.02400 0.03000 0.02100 0.01500 0.00000 0.00000 O4 0.02800 0.02200 0.03100 -0.00400 -0.00100 -0.00300 O5 0.02600 0.03100 0.02200 -0.00200 -0.00200 -0.00300