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