data_global _chemical_name_mineral 'Paracelsian' loop_ _publ_author_name 'Chiari G' 'Gazzoni G' 'Craig J R' 'Gibbs G V' 'Louisnathan S J' _journal_name_full 'American Mineralogist' _journal_volume 70 _journal_year 1985 _journal_page_first 969 _journal_page_last 974 _publ_section_title ; Two independent refinements of the structure of paracelsian, BaAl2Si2O8 Sample: CLG refinement ; _database_code_amcsd 0000998 _chemical_compound_source 'Benallt Mine, Carnarvonshire, U.K.' _chemical_formula_sum 'Ba Al2 Si2 O8' _cell_length_a 9.065 _cell_length_b 9.568 _cell_length_c 8.578 _cell_angle_alpha 90 _cell_angle_beta 90.01 _cell_angle_gamma 90 _cell_volume 744.004 _exptl_crystal_density_diffrn 3.352 _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 Ba 0.89785 0.41174 0.25107 0.00800 Al1 0.06420 0.19390 0.57260 0.00500 Si1 0.06880 0.19940 0.94110 0.00400 Al2 0.22420 0.92140 0.93020 0.00500 Si2 0.23070 0.91670 0.56250 0.00500 O1o 0.19480 0.08980 0.99910 0.00800 O1m 0.19250 0.07250 0.50380 0.01100 O2o 0.12720 0.36050 0.95560 0.01000 O2m 0.13150 0.36420 0.54450 0.00800 O3o 0.92980 0.18480 0.05950 0.00800 O3m 0.90910 0.18440 0.44950 0.00500 O4 0.01880 0.16570 0.76420 0.01200 O5 0.29160 0.91080 0.73900 0.00900