data_global _chemical_name_mineral 'Nasonite' loop_ _publ_author_name 'Giuseppetti G' 'Rossi G' 'Tadini C' _journal_name_full 'American Mineralogist' _journal_volume 56 _journal_year 1971 _journal_page_first 1174 _journal_page_last 1179 _publ_section_title ; The crystal structure of nasonite ; _database_code_amcsd 0000251 _chemical_formula_sum 'Pb6 Ca4 Cl2 Si6 O21' _cell_length_a 10.08 _cell_length_b 10.08 _cell_length_c 13.27 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 1167.677 _exptl_crystal_density_diffrn 5.628 _symmetry_space_group_name_H-M 'P 63/m' loop_ _space_group_symop_operation_xyz 'x,y,z' '-x+y,-x,1/2-z' 'x-y,x,1/2+z' 'y,-x+y,-z' '-y,x-y,z' 'x,y,1/2-z' '-x,-y,1/2+z' 'x-y,x,-z' '-x+y,-x,z' '-y,x-y,1/2-z' 'y,-x+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 Pb 0.25801 0.26493 0.10862 0.01824 Ca1 0.33333 0.66667 0.99360 0.01241 Ca2 0.33333 0.66667 0.25000 0.01203 Ca3 0.66667 0.33333 0.25000 0.00975 Cl1 0.00000 0.00000 0.25000 0.02710 Cl2 0.00000 0.00000 0.00000 0.02558 Si 0.02590 0.41980 0.36440 0.00659 O1 0.07100 0.32910 0.44440 0.02672 O2 0.85880 0.39490 0.62080 0.01368 O3 0.85450 0.37480 0.37250 0.02166 O4 0.07140 0.38300 0.25000 0.01748