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 = 450 C ; _database_code_amcsd 0018989 _chemical_compound_source 'Hungary' _chemical_formula_sum 'K.876 Na.071 Al2.916 S2 O14 H6' _cell_length_a 6.9916 _cell_length_b 6.9916 _cell_length_c 17.621 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 745.958 _exptl_crystal_density_diffrn 2.730 _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 0.03100 NaA 0.00000 0.00000 0.00000 0.07100 0.03100 Al 0.00000 0.50000 0.50000 0.97200 0.01300 S 0.00000 0.00000 0.30118 1.00000 0.01500 O1 0.00000 0.00000 0.38311 1.00000 0.02600 O2 0.21872 -0.21872 -0.06135 1.00000 0.02200 O3 0.12624 -0.12624 0.14042 1.00000 0.01800 H 0.18370 -0.18370 0.11040 1.00000 0.06100 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 0.03500 0.00000 0.02300 0.01700 0.00000 0.00000 NaA 0.03500 0.00000 0.02300 0.01700 0.00000 0.00000 Al 0.00900 0.01100 0.01900 0.00500 0.00000 0.00000 S 0.01600 0.00000 0.01600 0.00700 0.00000 0.00000 O1 0.03000 0.00000 0.01700 0.01500 0.00000 0.00000 O2 0.02500 0.02500 0.02300 0.01800 0.00100 0.00100 O3 0.01300 0.01300 0.02600 0.00500 0.00200 0.00200