data_global _chemical_name_mineral 'Bicchulite' loop_ _publ_author_name 'Sahl K' 'Chatterjee N D' _journal_name_full 'Zeitschrift fur Kristallographie' _journal_volume 146 _journal_year 1977 _journal_page_first 35 _journal_page_last 41 _publ_section_title ; The crystal structure of bicchulite, Ca2[Al2SiO6](OH)2 ; _database_code_amcsd 0010796 _chemical_compound_source 'Synthetic' _chemical_formula_sum 'Ca2 (Al2 Si) O8 H2' _cell_length_a 8.825 _cell_length_b 8.825 _cell_length_c 8.825 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 90 _cell_volume 687.297 _exptl_crystal_density_diffrn 2.824 _symmetry_space_group_name_H-M 'I -4 3 m' loop_ _space_group_symop_operation_xyz 'x,y,z' '1/2+x,1/2+y,1/2+z' '-z,x,-y' '1/2-z,1/2+x,1/2-y' '-y,z,-x' '1/2-y,1/2+z,1/2-x' '-x,y,-z' '1/2-x,1/2+y,1/2-z' 'x,-z,-y' '1/2+x,1/2-z,1/2-y' 'z,-y,-x' '1/2+z,1/2-y,1/2-x' 'y,-x,-z' '1/2+y,1/2-x,1/2-z' 'x,z,y' '1/2+x,1/2+z,1/2+y' 'z,y,x' '1/2+z,1/2+y,1/2+x' 'y,x,z' '1/2+y,1/2+x,1/2+z' '-z,-x,y' '1/2-z,1/2-x,1/2+y' '-y,-z,x' '1/2-y,1/2-z,1/2+x' '-x,-y,z' '1/2-x,1/2-y,1/2+z' 'z,-x,-y' '1/2+z,1/2-x,1/2-y' 'y,-z,-x' '1/2+y,1/2-z,1/2-x' 'x,-y,-z' '1/2+x,1/2-y,1/2-z' '-x,z,-y' '1/2-x,1/2+z,1/2-y' '-z,y,-x' '1/2-z,1/2+y,1/2-x' '-y,x,-z' '1/2-y,1/2+x,1/2-z' '-x,-z,y' '1/2-x,1/2-z,1/2+y' '-z,-y,x' '1/2-z,1/2-y,1/2+x' '-y,-x,z' '1/2-y,1/2-x,1/2+z' 'z,x,y' '1/2+z,1/2+x,1/2+y' 'y,z,x' '1/2+y,1/2+z,1/2+x' 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 0.14400 0.14400 0.14400 1.00000 0.00887 Al 0.25000 0.50000 0.00000 0.66667 0.00633 Si 0.25000 0.50000 0.00000 0.33333 0.00633 O 0.14900 0.14900 0.42400 1.00000 0.01900 O-H 0.38200 0.38200 0.38200 1.00000 0.01900