data_global _chemical_name_mineral 'Ilvaite' loop_ _publ_author_name 'Ghose S' 'Tsukimura K' 'Hatch D M' _journal_name_full 'Physics and Chemistry of Minerals' _journal_volume 16 _journal_year 1989 _journal_page_first 483 _journal_page_last 496 _publ_section_title ; Phase transitions in ilvaite, a mixed-valence iron silicate II. A single-crystal X-ray diffraction study and Landau theory of the monoclinic to orthorhombic phase transition induced by charge delocalization Sample: T = 320 K ; _database_code_amcsd 0007454 _chemical_formula_sum 'Fe3 Ca Si2 O9 H' _cell_length_a 13.0398 _cell_length_b 8.8217 _cell_length_c 5.8644 _cell_angle_alpha 90 _cell_angle_beta 90.244 _cell_angle_gamma 90 _cell_volume 674.595 _exptl_crystal_density_diffrn 4.025 _symmetry_space_group_name_H-M 'P 1 21/a 1' loop_ _space_group_symop_operation_xyz 'x,y,z' '1/2+x,1/2-y,z' '1/2-x,1/2+y,-z' '-x,-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_U_iso_or_equiv FeAo 0.89024 0.05003 0.00716 0.00790 FeAm 0.89007 0.05154 0.49299 0.00760 FeB 0.94058 0.73980 0.24900 0.00850 Ca 0.81289 0.37050 0.75215 0.00860 Si1 0.95949 0.36835 0.24943 0.00600 Si2 0.67946 0.22724 0.25129 0.00590 O1 0.00994 0.02927 0.74147 0.01080 O2o 0.93690 0.27210 0.01664 0.00840 O2m 0.93553 0.27220 0.48305 0.00800 O3 0.77724 0.10954 0.25435 0.00940 O4o 0.67128 0.32886 0.01924 0.00890 O4m 0.67086 0.33099 0.48207 0.00900 O5 0.58489 0.10080 0.25203 0.00820 O6 0.60183 0.02472 0.75188 0.01120 O-H7 0.79822 0.10942 0.74629 0.00860 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 FeAo 0.00740 0.00730 0.00910 -0.00010 -0.00050 0.00070 FeAm 0.00720 0.00680 0.00880 -0.00010 0.00030 -0.00070 FeB 0.00890 0.00700 0.00960 -0.00070 -0.00010 -0.00010 Ca 0.00760 0.00680 0.01140 0.00050 -0.00010 0.00000 Si1 0.00640 0.00590 0.00580 0.00010 -0.00010 -0.00010 Si2 0.00600 0.00550 0.00630 0.00060 0.00010 -0.00010 O1 0.00870 0.00910 0.01490 0.00160 -0.00100 0.00020 O2o 0.00950 0.00890 0.00700 -0.00200 -0.00120 0.00180 O2m 0.00960 0.00710 0.00740 -0.00170 0.00050 0.00130 O3 0.00820 0.00680 0.01040 0.00160 -0.00030 -0.00060 O4o 0.00990 0.00780 0.00900 -0.00050 -0.00010 0.00040 O4m 0.01140 0.00700 0.00860 0.00210 -0.00050 -0.00160 O5 0.00540 0.00740 0.01210 0.00020 -0.00040 -0.00080 O6 0.00980 0.00730 0.01660 -0.00180 0.00020 0.00030 O-H7 0.00780 0.00900 0.00910 0.00040 -0.00040 0.00080