data_global _chemical_name_mineral 'Rankamaite' loop_ _publ_author_name 'Atencio D' 'Contreira R R' 'Mills S J' 'Coutinho J M V' 'Honorato S B' 'Ayala A P' 'Ellena J' 'De Andrade M B' _journal_name_full 'American Mineralogist' _journal_volume 96 _journal_year 2011 _journal_page_first 1455 _journal_page_last 1460 _publ_section_title ; Rankamaite from the Urubu pegmatite, Itinga, Minas Gerais, Brazil: Crystal chemistry and Rietveld refinement Note: Identification of OH not reported ; _database_code_amcsd 0018556 _chemical_compound_source 'Urubu pegmatite, Itinga, Minas Gerais, Brazil' _chemical_formula_sum 'K1.26 Na2.22 Ta9.11 Nb1.29 Al.6 O31' _cell_length_a 17.224 _cell_length_b 17.687 _cell_length_c 3.9361 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 90 _cell_volume 1199.097 _exptl_crystal_density_diffrn 6.594 _symmetry_space_group_name_H-M 'C 2 2 2' loop_ _space_group_symop_operation_xyz 'x,y,z' '1/2+x,1/2+y,z' '-x,y,-z' '1/2-x,1/2+y,-z' 'x,-y,-z' '1/2+x,1/2-y,-z' '-x,-y,z' '1/2-x,1/2-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 K1 0.83220 0.00000 0.50000 0.63000 0.05699 Na2 0.49900 0.00000 0.50000 0.43000 0.05699 Na3 0.25000 0.25000 0.50000 0.68000 0.05699 Ta1 0.00000 0.00000 0.00000 0.71000 0.02533 Nb1 0.00000 0.00000 0.00000 0.29000 0.02533 Ta2 0.00000 0.67188 0.00000 0.72000 0.02533 Nb2 0.00000 0.67188 0.00000 0.28000 0.02533 Ta3 0.18037 0.39406 0.00000 0.85000 0.02533 Al3 0.18037 0.39406 0.00000 0.15000 0.02533 Ta4 0.11190 0.82225 0.00000 0.89000 0.02533 Nb4 0.11190 0.82225 0.00000 0.11000 0.02533 O1 0.32350 0.10610 0.50000 1.00000 0.01267 O2 0.61650 0.67770 0.50000 1.00000 0.01267 O3 0.13760 0.29150 0.00000 1.00000 0.01267 O4 0.07110 0.57800 0.00000 1.00000 0.01267 O5 0.27900 0.33770 0.00000 1.00000 0.01267 O6 0.11030 0.94420 0.00000 1.00000 0.01267 O7 0.00000 0.33340 0.50000 1.00000 0.01267 O8 0.00000 0.20110 0.00000 1.00000 0.01267 O9 0.71080 0.00000 0.00000 1.00000 0.01267 O10 0.00000 0.00000 0.50000 1.00000 0.01267