data_global _chemical_name_mineral 'Neptunite' loop_ _publ_author_name 'Kunz M' 'Armbruster T' 'Lager G A' 'Schultz A J' 'Goyette R J' 'Lottermoser W' 'Amthauer G' _journal_name_full 'Physics and Chemistry of Minerals' _journal_volume 18 _journal_year 1991 _journal_page_first 199 _journal_page_last 213 _publ_section_title ; Fe, Ti ordering and octahedral distortions in acentric neptunite: temperature dependent X-ray and neutron structure refinements and Mossbauer Spectroscopy Sample: T = 15 K ; _database_code_amcsd 0007530 _chemical_compound_source 'San Benito, California, USA' _chemical_formula_sum 'Na2 K Li Ti2 Fe2 Si8 O24' _cell_length_a 16.436 _cell_length_b 12.436 _cell_length_c 9.966 _cell_angle_alpha 90 _cell_angle_beta 115.63 _cell_angle_gamma 90 _cell_volume 1836.600 _exptl_crystal_density_diffrn 3.284 _symmetry_space_group_name_H-M 'C 1 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' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_U_iso_or_equiv Na1 0.26590 0.19580 0.31050 ? Na2 -0.26080 -0.19950 -0.30170 ? K1 0.00000 0.42060 0.25000 ? Li1 0.50250 0.43600 0.25500 ? Ti1 0.34280 0.32620 0.10320 ? Fe1 -0.33680 -0.31490 -0.09460 ? Ti2 0.09000 0.05000 0.11750 0.00380 Fe2 -0.08700 -0.06230 -0.11070 ? Si1 0.14650 0.40820 0.05990 ? Si1a -0.14390 -0.40580 -0.05990 ? Si2 0.52470 0.22580 0.08430 ? Si2a -0.52160 -0.22800 -0.08690 ? Si3 0.77020 0.47200 0.10740 ? Si3a -0.76950 -0.47450 -0.11000 ? Si4 0.89540 0.15120 0.07960 ? Si4a -0.89510 -0.14940 -0.08500 ? O1 0.95690 0.04980 0.06950 ? O1a -0.95080 -0.04610 -0.07390 ? O2 0.45590 0.32430 0.07120 ? O2a -0.45610 -0.32870 -0.06850 ? O3 0.10850 0.16810 0.25750 ? O3a -0.11040 -0.17000 -0.26830 ? O4 0.37050 0.43060 0.22230 ? O4a -0.37450 -0.44820 -0.25670 ? O5 0.20620 0.07340 0.09480 ? O5a -0.20770 -0.07870 -0.09070 ? O6 0.71190 0.36260 0.03910 ? O6a -0.70920 -0.36630 -0.05200 ? O7 0.21350 0.30920 0.07500 ? O7a -0.20510 -0.30440 -0.06780 ? O8 0.83170 0.49150 0.01840 ? O8a -0.83120 -0.48820 -0.01920 ? O9 0.15780 0.44980 0.22090 ? O9a -0.15870 -0.44790 -0.22380 ? O10 0.39620 0.21240 0.24980 ? O10a -0.39290 -0.20940 -0.25730 ? O11 0.46410 0.11510 0.02690 ? O11a -0.46010 -0.11850 -0.03220 ? O12 0.92860 0.26060 0.02560 ? O12a -0.93160 -0.25760 -0.03620 ? 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 Na1 0.00900 0.00800 0.00600 0.00040 0.00400 0.00040 Na2 0.00400 0.00500 0.00800 -0.00200 0.00300 -0.00200 K1 0.00430 0.01600 0.00600 0.00200 0.00200 0.00100 Li1 0.01200 0.01100 0.01100 -0.00600 0.00700 -0.00400 Ti1 0.00200 0.00400 0.00070 -0.00100 0.00070 0.00200 Fe1 0.00200 0.00200 0.00200 -0.00100 0.00140 -0.00200 Fe2 0.00310 0.00300 0.00370 -0.00080 0.00160 -0.00270 Si1 0.00290 0.00210 0.00320 -0.00010 0.00170 -0.00010 Si1a 0.00290 0.00210 0.00320 -0.00010 0.00170 -0.00010 Si2 0.00250 0.00280 0.00280 0.00020 0.00120 -0.00030 Si2a 0.00250 0.00280 0.00280 0.00020 0.00120 -0.00030 Si3 0.00250 0.00280 0.00200 -0.00040 0.00080 -0.00020 Si3a 0.00250 0.00280 0.00200 -0.00040 0.00080 -0.00020 Si4 0.00260 0.00250 0.00250 -0.00010 0.00150 0.00030 Si4a 0.00260 0.00250 0.00250 -0.00010 0.00150 0.00030 O1 0.00410 0.00310 0.00400 0.00060 0.00190 -0.00010 O1a 0.00410 0.00310 0.00400 0.00060 0.00190 -0.00010 O2 0.00460 0.00270 0.00470 0.00110 0.00240 0.00040 O2a 0.00460 0.00270 0.00470 0.00110 0.00240 0.00040 O3 0.00540 0.00480 0.00400 -0.00070 0.00270 -0.00050 O3a 0.00540 0.00480 0.00400 -0.00070 0.00270 -0.00050 O4 0.00570 0.00410 0.00550 0.00050 0.00340 -0.00030 O4a 0.00570 0.00410 0.00550 0.00050 0.00340 -0.00030 O5 0.00530 0.00290 0.00360 0.00110 0.00150 0.00010 O5a 0.00530 0.00290 0.00360 0.00110 0.00150 0.00010 O6 0.00390 0.00280 0.00440 -0.00030 0.00120 -0.00040 O6a 0.00390 0.00280 0.00440 -0.00030 0.00120 -0.00040 O7 0.00460 0.00410 0.00460 0.00030 0.00240 -0.00030 O7a 0.00460 0.00410 0.00460 0.00030 0.00240 -0.00030 O8 0.00520 0.00320 0.00480 0.00000 0.00350 0.00070 O8a 0.00520 0.00320 0.00480 0.00000 0.00350 0.00070 O9 0.00420 0.00650 0.00240 0.00040 0.00140 -0.00050 O9a 0.00420 0.00650 0.00240 0.00040 0.00140 -0.00050 O10 0.00410 0.00390 0.00340 -0.00020 0.00060 0.00020 O10a 0.00410 0.00390 0.00340 -0.00020 0.00060 0.00020 O11 0.00310 0.00320 0.00500 -0.00090 0.00170 -0.00050 O11a 0.00310 0.00320 0.00500 -0.00090 0.00170 -0.00050 O12 0.00520 0.00320 0.00480 -0.00020 0.00330 0.00070 O12a 0.00520 0.00320 0.00480 -0.00020 0.00330 0.00070