data_global _chemical_name_mineral 'Neptunite' loop_ _publ_author_name 'Cannillo E' 'Mazzi F' 'Rossi G' _journal_name_full 'Acta Crystallographica' _journal_volume 21 _journal_year 1966 _journal_page_first 200 _journal_page_last 208 _publ_section_title ; The crystal structure of neptunite ; _database_code_amcsd 0018847 _chemical_compound_source 'San Benito, California, USA' _chemical_formula_sum '(Fe2 Ti2) Na2 K Li Si8 O24' _cell_length_a 16.46 _cell_length_b 12.50 _cell_length_c 10.01 _cell_angle_alpha 90 _cell_angle_beta 115.43 _cell_angle_gamma 90 _cell_volume 1860.008 _exptl_crystal_density_diffrn 3.243 _symmetry_space_group_name_H-M 'C 1 2/c 1' 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,1/2-z' '1/2-x,1/2+y,1/2-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 Fe2+1 0.34020 0.32110 0.09830 0.50000 0.01925 Ti1 0.34020 0.32110 0.09830 0.50000 0.01925 Fe2+2 0.08830 0.05610 0.11280 0.50000 0.01925 Ti2 0.08830 0.05610 0.11280 0.50000 0.01925 Na 0.26400 0.19830 0.30940 1.00000 0.02609 K 0.00000 0.42040 0.25000 1.00000 0.02178 Li 0.50000 0.43530 0.25000 1.00000 0.05661 Si1 0.14520 0.40600 0.05660 1.00000 0.01013 Si2 0.52330 0.22800 0.08550 1.00000 0.01013 Si3 0.76980 0.47410 0.10830 1.00000 0.01013 Si4 0.89420 0.14910 0.08160 1.00000 0.01013 O1 0.95380 0.04460 0.06880 1.00000 0.01824 O2 0.45490 0.32530 0.06660 1.00000 0.01824 O3 0.10990 0.16730 0.26640 1.00000 0.01824 O4 0.37230 0.43870 0.23480 1.00000 0.01824 O5 0.20500 0.07960 0.08880 1.00000 0.01824 O6 0.71220 0.36770 0.04270 1.00000 0.01824 O7 0.20880 0.30770 0.07070 1.00000 0.01824 O8 0.83390 0.49190 0.02390 1.00000 0.01824 O9 0.15920 0.45050 0.21480 1.00000 0.01824 O10 0.39750 0.21040 0.25410 1.00000 0.01824 O11 0.46130 0.11730 0.02390 1.00000 0.01824 O12 0.92910 0.25620 0.03160 1.00000 0.01824