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 = 360 K ; _database_code_amcsd 0007456 _chemical_formula_sum 'Fe3 Ca Si2 O9 H' _cell_length_a 13.0497 _cell_length_b 8.8291 _cell_length_c 5.8652 _cell_angle_alpha 90 _cell_angle_beta 90.029 _cell_angle_gamma 90 _cell_volume 675.771 _exptl_crystal_density_diffrn 4.018 _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 0.89027 0.05067 0.00689 0.00950 FeAm 0.89017 0.05094 0.49302 0.00920 FeB 0.94047 0.73949 0.24974 0.01020 Ca 0.81298 0.37052 0.75032 0.01020 Si1 0.95956 0.36835 0.24987 0.00690 Si2 0.67949 0.22708 0.25028 0.00720 O1 0.00982 0.02881 0.74902 0.01370 O2o 0.93645 0.27245 0.01641 0.00930 O2m 0.93615 0.27195 0.48393 0.00900 O3 0.77704 0.10967 0.25046 0.00960 O4o 0.67093 0.32970 0.01853 0.00960 O4m 0.67097 0.32959 0.48165 0.01040 O5 0.58527 0.10120 0.25028 0.00940 O6 0.60194 0.02447 0.74977 0.01280 O-H7 0.79794 0.10926 0.74962 0.00970 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 0.01090 0.00870 0.00900 -0.00010 -0.00080 0.00090 FeAm 0.01070 0.00850 0.00860 -0.00030 0.00040 -0.00050 FeB 0.01280 0.00870 0.00930 -0.00070 -0.00030 -0.00020 Ca 0.01120 0.00820 0.01140 0.00100 -0.00060 0.00000 Si1 0.00890 0.00680 0.00520 0.00000 -0.00020 -0.00040 Si2 0.00920 0.00710 0.00550 0.00030 -0.00040 0.00030 O1 0.01460 0.01160 0.01490 0.00040 0.00000 -0.00030 O2o 0.01240 0.01020 0.00530 -0.00130 0.00060 -0.00140 O2m 0.01210 0.01020 0.00490 -0.00050 -0.00080 0.00150 O3 0.01020 0.00920 0.00970 0.00190 -0.00050 -0.00060 O4o 0.01170 0.00910 0.00820 0.00030 0.00000 0.00130 O4m 0.01270 0.01100 0.00760 0.00080 -0.00010 -0.00260 O5 0.01050 0.00710 0.01090 0.00170 0.00040 -0.00060 O6 0.01290 0.01020 0.01540 -0.00280 -0.00030 -0.00040 O-H7 0.01130 0.00900 0.00900 0.00140 0.00070 0.00100