data_global _chemical_name_mineral 'Ilvaite' loop_ _publ_author_name 'Ghose S' 'Hewat A W' 'Marezio M' _journal_name_full 'Physics and Chemistry of Minerals' _journal_volume 11 _journal_year 1984 _journal_page_first 67 _journal_page_last 74 _publ_section_title ; A neutron powder diffraction study of the crystal and magnetic structures of ilvaite from 305 K to 5 K - a mixed valence iron silicate with an electronic transition Sample: T = 150 K ; _database_code_amcsd 0007363 _chemical_formula_sum 'Ca (Fe2.8 Mn.2) Si2 O9 H' _cell_length_a 13.0244 _cell_length_b 8.8006 _cell_length_c 5.8445 _cell_angle_alpha 90 _cell_angle_beta 90.233 _cell_angle_gamma 90 _cell_volume 669.906 _exptl_crystal_density_diffrn 4.051 _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_occupancy _atom_site_U_iso_or_equiv Ca 0.81410 0.36830 0.74890 1.00000 0.03154 FeM11 0.88830 0.05200 0.01010 0.92500 0.00836 MnM11 0.88830 0.05200 0.01010 0.07500 0.00836 FeM12 0.89040 0.05020 0.48910 0.97500 0.00836 MnM12 0.89040 0.05020 0.48910 0.02500 0.00836 FeM2 0.94140 0.74440 0.24960 0.90000 0.00684 MnM2 0.94140 0.74440 0.24960 0.10000 0.00684 Si1 0.95960 0.36750 0.24260 1.00000 0.01317 Si2 0.67730 0.22960 0.24710 1.00000 0.01317 O1 0.00660 0.02620 0.73190 1.00000 0.01849 O21 0.93760 0.27270 0.01170 1.00000 0.01849 O22 0.93330 0.27310 0.48560 1.00000 0.01849 O5 0.58550 0.10360 0.25840 1.00000 0.01849 O6 0.60020 0.02710 0.75200 1.00000 0.01849 O3 0.77760 0.10780 0.25620 1.00000 0.01849 O41 0.66840 0.33120 0.01620 1.00000 0.01849 O42 0.67210 0.33110 0.47890 1.00000 0.01849 O7 0.79610 0.10600 0.74250 1.00000 0.01849 H 0.73770 0.06070 0.73780 1.00000 0.02584