data_global _chemical_name_mineral 'Beryl' loop_ _publ_author_name 'Aurisicchio C' 'Fioravanti G' 'Grubessi O' 'Zanazzi P F' _journal_name_full 'American Mineralogist' _journal_volume 73 _journal_year 1988 _journal_page_first 826 _journal_page_last 837 _publ_section_title ; Reappraisal of the crystal chemistry of beryl Sample: 16 ; _database_code_amcsd 0001181 _chemical_compound_source 'Fort Victoria field, Zimbabwe' _chemical_formula_sum 'Si6.003 Be2.985 Li.006 Al1.979 Fe.024 O18 Na.026' _cell_length_a 9.2097 _cell_length_b 9.2097 _cell_length_c 9.1943 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 675.368 _exptl_crystal_density_diffrn 2.650 _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 Si1 0.38760 0.11580 0.00000 1.00000 ? Be 0.50000 0.00000 0.25000 0.99500 0.00300 Li 0.50000 0.00000 0.25000 0.00200 0.00300 Si2 0.50000 0.00000 0.25000 0.00100 0.00300 Al1 0.50000 0.00000 0.25000 0.00100 0.00300 Al2 0.66667 0.33333 0.25000 0.98800 ? Fe 0.66667 0.33333 0.25000 0.01200 ? O1 0.31030 0.23690 0.00000 1.00000 ? O2 0.49890 0.14560 0.14520 1.00000 ? Na 0.00000 0.00000 0.25000 0.02600 ? loop_ _atom_site_aniso_label _atom_site_aniso_U_11 _atom_site_aniso_U_22 _atom_site_aniso_U_33 _atom_site_aniso_U_12 _atom_site_aniso_U_13 _atom_site_aniso_U_23 Si1 0.00120 0.00110 0.00010 0.00060 0.00000 0.00000 Al2 0.00390 0.00390 0.00250 0.00190 0.00000 0.00000 Fe 0.00390 0.00390 0.00250 0.00190 0.00000 0.00000 O1 0.00730 0.00480 0.00910 0.00510 0.00000 0.00000 O2 0.00500 0.00310 0.00330 0.00230 -0.00210 -0.00060 Na 0.07760 0.07760 0.03620 0.03880 0.00000 0.00000