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 = 295 K ; _database_code_amcsd 0007453 _chemical_formula_sum 'Fe3 Ca Si2 O9 H' _cell_length_a 13.0387 _cell_length_b 8.8204 _cell_length_c 5.8640 _cell_angle_alpha 90 _cell_angle_beta 90.266 _cell_angle_gamma 90 _cell_volume 674.391 _exptl_crystal_density_diffrn 4.026 _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 0.89019 0.04983 0.00727 0.00720 FeAm 0.89004 0.05172 0.49272 0.00670 FeB 0.94063 0.73996 0.24886 0.00760 Ca 0.81296 0.37035 0.75267 0.00770 Si1 0.95955 0.36831 0.24296 0.00520 Si2 0.67949 0.22724 0.25156 0.00530 O1 0.00986 0.02900 0.73935 0.01020 O2o 0.93712 0.27206 0.01614 0.00760 O2m 0.93547 0.27264 0.48315 0.00800 O3 0.77717 0.10951 0.25521 0.00720 O4o 0.67137 0.32852 0.01910 0.00780 O4m 0.67068 0.33130 0.48206 0.00800 O5 0.58481 0.10087 0.25308 0.00740 O6 0.60193 0.02508 0.75216 0.01040 O-H7 0.79767 0.10973 0.74510 0.00770 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 0.00670 0.00640 0.00860 -0.00020 -0.00030 0.00060 FeAm 0.00600 0.00610 0.00800 -0.00020 0.00030 -0.00040 FeB 0.00810 0.00610 0.00870 -0.00070 -0.00010 -0.00030 Ca 0.00660 0.00600 0.01070 0.00060 0.00000 -0.00010 Si1 0.00540 0.00470 0.00570 0.00000 0.00030 0.00020 Si2 0.00470 0.00550 0.00580 0.00020 0.00010 0.00010 O1 0.00790 0.00950 0.01340 0.00170 -0.00050 -0.00020 O2o 0.00900 0.00690 0.00720 -0.00090 -0.00030 -0.00140 O2m 0.00890 0.00750 0.00770 -0.00110 -0.00060 0.00060 O3 0.00570 0.00640 0.00970 0.00170 0.00030 -0.00010 O4o 0.00870 0.00690 0.00790 0.00000 0.00040 0.00070 O4m 0.00860 0.00750 0.00800 0.00000 0.00050 -0.00200 O5 0.00510 0.00640 0.01070 0.00010 0.00010 -0.00170 O6 0.00750 0.00650 0.01740 -0.00220 0.00040 0.00080 O-H7 0.00690 0.00820 0.00810 0.00110 0.00090 0.00010