data_global _chemical_name_mineral 'Sillimanite' loop_ _publ_author_name 'Winter J K' 'Ghose S' _journal_name_full 'American Mineralogist' _journal_volume 64 _journal_year 1979 _journal_page_first 573 _journal_page_last 586 _publ_section_title ; Thermal expansion and high-temperature crystal chemistry of the Al2SiO5 polymorphs T = 800 deg C ; _database_code_amcsd 0000726 _chemical_formula_sum 'Al2 Si O5' _cell_length_a 7.4998 _cell_length_b 7.7255 _cell_length_c 5.7978 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 90 _cell_volume 335.923 _exptl_crystal_density_diffrn 3.204 _symmetry_space_group_name_H-M 'P b n m' loop_ _space_group_symop_operation_xyz 'x,y,z' 'x,y,1/2-z' '-x,-y,1/2+z' '1/2+x,1/2-y,1/2+z' '1/2-x,1/2+y,1/2-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 Al1 0.00000 0.00000 0.00000 Al2 0.14120 0.34610 0.25000 Si 0.15230 0.34100 0.75000 O1 0.35940 0.41000 0.75000 O2 0.35700 0.43520 0.25000 O3 0.47770 0.00050 0.75000 O4 0.12470 0.22500 0.51450 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 Al1 0.01140 0.01603 0.01345 0.00000 -0.00044 -0.00023 Al2 0.01225 0.01633 0.01447 -0.00088 0.00000 0.00000 Si 0.01054 0.01421 0.01362 -0.00176 0.00000 0.00000 O1 0.01140 0.02177 0.01822 -0.00558 0.00000 0.00000 O2 0.01140 0.02207 0.01703 -0.00499 0.00000 0.00000 O3 0.02935 0.02993 0.03661 -0.01673 0.00000 0.00000 O4 0.02223 0.01693 0.01413 -0.00558 -0.00088 -0.00045