data_global _chemical_name_mineral 'Beryl' loop_ _publ_author_name 'Artioli G' 'Rinaldi R' 'Stahl K' 'Zanazzi P F' _journal_name_full 'American Mineralogist' _journal_volume 78 _journal_year 1993 _journal_page_first 762 _journal_page_last 768 _publ_section_title ; Structure refinements of beryl by single-crystal neutron and X-ray diffraction Sample no. 1, morganite, probed with neutrons, T = 30 K ; _database_code_amcsd 0001602 _chemical_formula_sum 'Si6 Be2.664 Li.315 Al2 O18.72 Cs.083 Na.24 H1.476' _cell_length_a 9.197 _cell_length_b 9.197 _cell_length_c 9.202 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 674.070 _exptl_crystal_density_diffrn 2.790 _symmetry_space_group_name_H-M 'P 6/m c c' loop_ _space_group_symop_operation_xyz 'x,y,z' '-x,-x+y,1/2+z' 'x,x-y,1/2-z' '-x+y,-x,-z' 'x-y,x,z' '-y,-x,1/2+z' 'y,x,1/2-z' 'y,-x+y,-z' '-y,x-y,z' 'x-y,-y,1/2+z' '-x+y,y,1/2-z' 'x,y,-z' '-x,-y,z' 'x,x-y,1/2+z' '-x,-x+y,1/2-z' 'x-y,x,-z' '-x+y,-x,z' 'y,x,1/2+z' '-y,-x,1/2-z' '-y,x-y,-z' 'y,-x+y,z' '-x+y,y,1/2+z' 'x-y,-y,1/2-z' '-x,-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 Si 0.38950 0.11820 0.00000 1.00000 0.00431 Be 0.50000 0.00000 0.25000 0.88800 0.00418 Li 0.50000 0.00000 0.25000 0.10500 0.00418 Al 0.66667 0.33333 0.25000 1.00000 0.00329 O1 0.30650 0.23570 0.00000 1.00000 0.00823 O2 0.49880 0.14680 0.14490 1.00000 0.00785 OW 0.00000 0.00000 0.25000 0.72000 0.02533 Cs 0.00000 0.00000 0.25000 0.08300 0.02533 Na 0.00000 0.00000 0.00000 0.24000 0.01900 H 0.09200 0.06200 0.31600 0.12300 0.06333