data_global _chemical_name_mineral 'Cryolite' loop_ _publ_author_name 'Ross K C' 'Mitchell R H' 'Chakhmouradian A R' _journal_name_full 'Journal of Solid State Chemistry' _journal_volume 172 _journal_year 2003 _journal_page_first 95 _journal_page_last 101 _publ_section_title ; The crystal structure of synthetic simmonsite, Na2LiAlF6 ; _database_code_amcsd 0014034 _chemical_compound_source 'Synthetic' _chemical_formula_sum 'Na3 Al F6' _cell_length_a 5.4054 _cell_length_b 5.5934 _cell_length_c 7.7672 _cell_angle_alpha 90 _cell_angle_beta 89.81 _cell_angle_gamma 90 _cell_volume 234.837 _exptl_crystal_density_diffrn 2.969 _symmetry_space_group_name_H-M 'P 1 21/n 1' loop_ _space_group_symop_operation_xyz 'x,y,z' '1/2+x,1/2-y,1/2+z' '1/2-x,1/2+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_U_iso_or_equiv Na2 0.51380 0.55200 0.25180 0.02913 Na1 0.50000 0.00000 0.50000 0.02026 Al1 0.50000 0.00000 0.00000 0.02280 F1 0.22550 0.17650 0.95300 0.02026 F2 0.33530 0.72850 0.93620 0.01773 F3 0.39700 0.95640 0.21820 0.01773