data_global
_chemical_name_mineral 'Tarapacaite'
loop_
_publ_author_name
'McGinnety J A'
_journal_name_full 'Acta Crystallographica, Section B'
_journal_volume 28 
_journal_year 1972
_journal_page_first 2845
_journal_page_last 2852
_publ_section_title
;
 Redetermination of the structures of potassium sulphate and potassium chromate:
 the effect of electrostatic crystal forces upon observed bond length
;
_database_code_amcsd 0009457
_chemical_formula_sum 'K2 Cr O4'
_cell_length_a 7.663
_cell_length_b 10.388
_cell_length_c 5.922
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 471.410
_exptl_crystal_density_diffrn      2.736
_symmetry_space_group_name_H-M 'P n a m'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  'x,y,1/2-z'
  '-x,-y,1/2+z'
  '1/2-x,1/2+y,1/2+z'
  '1/2+x,1/2-y,1/2-z'
  '1/2+x,1/2-y,z'
  '1/2-x,1/2+y,-z'
  '-x,-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
K1   0.66544   0.41449   0.25000
K2  -0.01105   0.69980   0.25000
Cr   0.22900   0.42059   0.25000
O1   0.01550   0.42000   0.25000
O2   0.30240   0.57000   0.25000
O3   0.30220   0.34710   0.02330
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
K1 0.01636 0.03040 0.02628 -0.00218 0.00000 0.00000
K2 0.01514 0.01826 0.02537 0.00048 0.00000 0.00000
Cr 0.00994 0.01389 0.01530 -0.00032 0.00000 0.00000
O1 0.01220 0.03881 0.05152 -0.00282 0.00000 0.00000
O2 0.02410 0.01968 0.04033 -0.00686 0.00000 0.00000
O3 0.03659 0.03717 0.02274 0.01049 0.00207 -0.00997