data_global _amcsd_formula_title 'K6Nb6Si4O26' loop_ _publ_author_name 'Choisnet J' 'Nguyen N' 'Groult D' 'Raveau B' _journal_name_full 'Materials Research Bulletin' _journal_volume 11 _journal_year 1976 _journal_page_first 887 _journal_page_last 894 _publ_section_title ; De nouveaux oxydes a reseau forme d'octahedres NbO6 (TaO6) et de groupes Si2O7: Les phases A3Ta6Si4O26 (A = Ba,Sr) et K6M6Si4O26 (M = Nb,Ta) ; _database_code_amcsd 0014246 _chemical_formula_sum 'K3 Nb3 Si2 O13' _cell_length_a 9.032 _cell_length_b 9.032 _cell_length_c 8.041 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 568.079 _exptl_crystal_density_diffrn 3.859 _symmetry_space_group_name_H-M 'P -6 2 m' loop_ _space_group_symop_operation_xyz 'x,y,z' '-x,-x+y,z' '-x+y,-x,-z' 'y,x,-z' '-y,x-y,z' 'x-y,-y,z' 'x,y,-z' '-x,-x+y,-z' '-x+y,-x,z' 'y,x,z' '-y,x-y,-z' 'x-y,-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_U_iso_or_equiv K1 0.59100 0.00000 0.50000 0.03534 K2 0.60400 0.00000 0.00000 0.00925 Nb 0.23900 0.00000 0.23400 0.01013 Si 0.33333 0.66667 0.20300 0.01583 O1 0.33333 0.66667 0.00000 0.00760 O2 0.25000 0.00000 0.00000 0.00127 O3 0.81600 0.00000 0.23700 0.01646 O4 0.49400 0.17600 0.26500 0.00127 O5 0.26800 0.00000 0.50000 0.01634