data_global
_chemical_name_mineral 'Richterite'
loop_
_publ_author_name
'Hawthorne F C'
'Della Ventura G'
'Robert J-L'
'Welch M D'
'Jenkins D M'
_journal_name_full 'American Mineralogist'
_journal_volume 82 
_journal_year 1997
_journal_page_first 708
_journal_page_last 716
_publ_section_title
;
 A Rietveld and infrared study of synthetic amphiboles along the
 potassium-richterite-tremolite join
 Sample: Kr40
;
_database_code_amcsd 0001917
_chemical_formula_sum 'Si8 Mg5 (Ca1.6 Na.4) K.4 O24'
_cell_length_a 9.9548
_cell_length_b 18.021
_cell_length_c 5.2735
_cell_angle_alpha 90
_cell_angle_beta 104.724
_cell_angle_gamma 90
_cell_volume 914.975
_exptl_crystal_density_diffrn      2.973
_symmetry_space_group_name_H-M 'C 1 2/m 1'
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
Si1   0.27840   0.08470   0.29860   1.00000
Si2   0.28390   0.17010   0.80080   1.00000
Mg1   0.00000   0.08740   0.50000   1.00000
Mg2   0.00000   0.17930   0.00000   1.00000
Mg3   0.00000   0.00000   0.00000   1.00000
Ca4   0.00000   0.27610   0.50000   0.80000
Na4   0.00000   0.27610   0.50000   0.20000
KA   0.01000   0.50000   0.02200   0.20000
O1   0.11470   0.08840   0.22170   1.00000
O2   0.10410   0.17030   0.71850   1.00000
O3   0.10500   0.00000   0.71630   1.00000
O4   0.35290   0.24930   0.78010   1.00000
O5   0.33890   0.13020   0.08950   1.00000
O6   0.33660   0.11500   0.59800   1.00000
O7   0.33300   0.00000   0.30570   1.00000