data_global _amcsd_formula_title '(Na.75K.25)AlGeO4' loop_ _publ_author_name 'Hammond R P' 'Barbier J' _journal_name_full 'Acta Crystallographica, Section B' _journal_volume 54 _journal_year 1998 _journal_page_first 211 _journal_page_last 220 _publ_section_title ; Monoclinic and hexagonal nepheline structures of (Na3/4K1/4)AlGeO4 Note: monoclinic nepheline ; _database_code_amcsd 0009904 _chemical_compound_source 'Synthetic' _chemical_formula_sum 'Na3 K Al4 Ge4 O16' _cell_length_a 10.0477 _cell_length_b 8.5764 _cell_length_c 10.2118 _cell_angle_alpha 90 _cell_angle_beta 119.0350 _cell_angle_gamma 90 _cell_volume 769.389 _exptl_crystal_density_diffrn 3.291 _symmetry_space_group_name_H-M 'P 1 21 1' loop_ _space_group_symop_operation_xyz 'x,y,z' '-x,1/2+y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_U_iso_or_equiv Na1 0.43620 0.42890 0.45330 0.02010 Na2 0.56100 0.42880 0.99820 0.02220 Na3 0.00730 0.92930 0.43790 0.02280 K4 0.01210 0.42680 0.00770 0.03810 All 0.34740 0.73800 0.66490 0.00800 Al2 0.24480 0.23880 0.90320 0.00840 Al3 0.09010 0.24220 0.34140 0.00770 Al4 0.68100 0.24570 0.76310 0.00800 Gel 0.34742 0.12270 0.66563 0.00990 Ge2 0.24343 0.61970 0.90195 0.00950 Ge3 0.08980 0.61570 0.34079 0.00970 Ge4 0.68052 0.61120 0.76134 0.00890 O1 0.48460 0.23340 0.64920 0.01800 O2 0.73410 0.43070 0.72920 0.01270 O3 0.73840 0.24000 0.95310 0.01700 O4 0.05270 0.60840 0.77210 0.01600 O5 0.77720 0.10330 0.72090 0.01700 O6 0.48630 0.62940 0.64730 0.01900 O7 0.35870 0.15270 0.84050 0.01800 O8 0.73370 0.62120 0.95060 0.01700 O9 0.05110 0.24550 0.77150 0.01600 O10 0.01770 0.42970 0.33320 0.02200 Oll 0.30400 0.42930 0.96110 0.02300 O12 0.22520 0.25520 0.27990 0.01300 O13 0.16560 0.68340 0.52100 0.02000 O14 0.39000 -0.06750 0.65020 0.02700 O15 0.16740 0.17000 0.52650 0.02600 O16 0.35650 0.70260 0.83630 0.02100