data_global _chemical_name_mineral 'Beryl' loop_ _publ_author_name 'Sherriff B L' 'Grundy H D' 'Hartman J S' 'Hawthorne F C' 'Cerny P' _journal_name_full 'The Canadian Mineralogist' _journal_volume 29 _journal_year 1991 _journal_page_first 271 _journal_page_last 285 _publ_section_title ; The incorporation of alkalis in beryl: multi-nuclear MAS NMR and crystal-structure study Sample: SHEE-1-6 ; _database_code_amcsd 0005258 _chemical_compound_source 'SHEE-1 pegmatite dike, eastern end of Shatford Lake, southeastern Manitoba, Canada' _chemical_formula_sum 'Si6 Be3 (Al1.96 Fe.04) O18 Na.03' _cell_length_a 9.206 _cell_length_b 9.206 _cell_length_c 9.185 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 674.143 _exptl_crystal_density_diffrn 2.657 _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 0.38750 0.11580 0.00000 1.00000 0.00290 Be 0.50000 0.00000 0.25000 1.00000 0.00570 Al 0.66667 0.33333 0.25000 0.98000 0.00460 Fe 0.66667 0.33333 0.25000 0.02000 0.00460 O1 0.30950 0.23620 0.00000 1.00000 0.00800 O2 0.49870 0.14540 0.14540 1.00000 0.00530 Na 0.00000 0.00000 0.00000 0.03000 0.01500