data_global _chemical_name_mineral 'Ferrihydrite' loop_ _publ_author_name 'Michel F M' 'Ehm L' 'Antao S M' 'Lee P L' 'Chupas P J' 'Liu G' 'Strongin D R' 'Schoonen M A A' 'Phillips B L' 'Parise J B' _journal_name_full 'Science' _journal_volume 316 _journal_year 2007 _journal_page_first 1726 _journal_page_last 1729 _publ_section_title ; The structure of ferrihydrite, a nanocrystalline material Sample: Fhyd2 ; _database_code_amcsd 0015441 _chemical_compound_source 'Synthetic' _chemical_formula_sum 'Fe4.75 (O8 H)' _cell_length_a 5.958 _cell_length_b 5.958 _cell_length_c 8.965 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 275.602 _exptl_crystal_density_diffrn 4.751 _symmetry_space_group_name_H-M 'P 63 m c' loop_ _space_group_symop_operation_xyz 'x,y,z' '-x,-x+y,1/2+z' 'x-y,x,1/2+z' '-y,-x,z' '-y,x-y,z' 'x-y,-y,1/2+z' '-x,-y,1/2+z' 'x,x-y,z' '-x+y,-x,z' 'y,x,1/2+z' 'y,-x+y,1/2+z' '-x+y,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 Fe1 0.16880 0.83120 0.63560 1.01000 0.00800 Fe2 0.33333 0.66667 0.34140 0.90000 0.00800 Fe3 0.33333 0.66667 0.95380 0.85000 0.00800 O-H1 0.00000 0.00000 0.01470 1.00000 0.01400 O2 0.33333 0.66667 0.73530 1.00000 0.01400 O3 0.16710 0.83290 0.25470 1.00000 0.01400 O4 0.52380 0.47620 0.00530 1.00000 0.01400