data_global _chemical_name_mineral 'Alunite' loop_ _publ_author_name 'Zema M' 'Callegari A M' 'Tarantino S C' 'Gasparini E' 'Ghigna P' _journal_name_full 'Mineralogical Magazine' _journal_volume 76 _journal_year 2012 _journal_page_first 613 _journal_page_last 623 _publ_section_title ; Thermal expansion of alunite up to dehydroxylation and collapse of the crystal structure Note: T = 500 C ; _database_code_amcsd 0018990 _chemical_compound_source 'Hungary' _chemical_formula_sum 'K.876 Na.071 Al2.796 S2 O14' _cell_length_a 6.9935 _cell_length_b 6.9935 _cell_length_c 17.640 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 747.168 _exptl_crystal_density_diffrn 2.663 _symmetry_space_group_name_H-M 'R -3 m' loop_ _space_group_symop_operation_xyz 'x,y,z' '2/3+x,1/3+y,1/3+z' '1/3+x,2/3+y,2/3+z' 'x,x-y,z' '2/3+x,1/3+x-y,1/3+z' '1/3+x,2/3+x-y,2/3+z' 'y,x,-z' '2/3+y,1/3+x,1/3-z' '1/3+y,2/3+x,2/3-z' '-x+y,y,z' '2/3-x+y,1/3+y,1/3+z' '1/3-x+y,2/3+y,2/3+z' '-x,-x+y,-z' '2/3-x,1/3-x+y,1/3-z' '1/3-x,2/3-x+y,2/3-z' '-y,-x,z' '2/3-y,1/3-x,1/3+z' '1/3-y,2/3-x,2/3+z' 'x-y,-y,-z' '2/3+x-y,1/3-y,1/3-z' '1/3+x-y,2/3-y,2/3-z' 'y,-x+y,-z' '2/3+y,1/3-x+y,1/3-z' '1/3+y,2/3-x+y,2/3-z' '-x+y,-x,z' '2/3-x+y,1/3-x,1/3+z' '1/3-x+y,2/3-x,2/3+z' '-x,-y,-z' '2/3-x,1/3-y,1/3-z' '1/3-x,2/3-y,2/3-z' '-y,x-y,z' '2/3-y,1/3+x-y,1/3+z' '1/3-y,2/3+x-y,2/3+z' 'x-y,x,-z' '2/3+x-y,1/3+x,1/3-z' '1/3+x-y,2/3+x,2/3-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 KA 0.00000 0.00000 0.00000 0.87600 0.03300 NaA 0.00000 0.00000 0.00000 0.07100 0.03300 Al 0.00000 0.50000 0.50000 0.93200 0.02600 S 0.00000 0.00000 0.30100 1.00000 0.03000 O1 0.00000 0.00000 0.38270 1.00000 0.04100 O2 0.21860 -0.21860 -0.06190 1.00000 0.03500 O3 0.12660 -0.12660 0.14030 1.00000 0.03400 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 KA 0.02900 0.00000 0.04200 0.01400 0.00000 0.00000 NaA 0.02900 0.00000 0.04200 0.01400 0.00000 0.00000 Al 0.01100 0.01300 0.05400 0.00500 0.00100 0.00100 S 0.01900 0.00000 0.05100 0.00900 0.00000 0.00000 O1 0.03500 0.00000 0.05300 0.01800 0.00000 0.00000 O2 0.03200 0.03200 0.04800 0.02100 0.00100 0.00100 O3 0.01600 0.01600 0.06700 0.00700 0.00100 0.00100