data_global _chemical_name_mineral 'Hurlbutite' loop_ _publ_author_name 'Lindbloom J T' 'Gibbs G V' 'Ribbe P H' _journal_name_full 'American Mineralogist' _journal_volume 59 _journal_year 1974 _journal_page_first 1267 _journal_page_last 1271 _publ_section_title ; The crystal structure of hurlbutite: A comparison with danburite and anorthite ; _database_code_amcsd 431 _chemical_formula_sum 'Ca P2 Be2 O8' _cell_length_a 8.299 _cell_length_b 8.782 _cell_length_c 7.798 _cell_angle_alpha 90.0 _cell_angle_beta 90.5 _cell_angle_gamma 90.0 _cell_volume 568.311 _exptl_crystal_density_diffrn 2.899 _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 Ca 0.3869 0.0863 0.244 0.00836 P1m 0.2626 0.4177 0.4395 0.00912 Be1o 0.268 0.4215 0.0707 0.0095 P2o 0.0588 0.1976 -0.0606 0.00481 Be2m 0.0566 0.1949 0.5698 0.00912 O1o 0.1928 0.0888 0.0028 0.0076 O1m 0.1881 0.0737 0.4965 0.00747 O2o 0.1224 0.3634 -0.055 0.00684 O2m 0.1296 0.3689 0.563 0.00988 O3o 0.4215 0.3096 0.0675 0.00912 O3m 0.4034 0.3065 0.4371 0.00773 O4 0.4999 0.6553 0.2388 0.00925 O5 0.1854 0.4199 0.2591 0.00975