data_global
_chemical_name_mineral 'Combeite'
loop_
_publ_author_name
'Fischer R X'
'Tillmanns E'
_journal_name_full 'Acta Crystallographica, Section C'
_journal_volume 43 
_journal_year 1987
_journal_page_first 1852
_journal_page_last 1854
_publ_section_title
;
 Revised data for combeite, Na2Ca2Si3O9
;
_database_code_amcsd 0010051
_chemical_compound_source 'synthetic high-temperature form'
_chemical_formula_sum 'Na2.64 Ca1.5 Si3 O9'
_cell_length_a 10.429
_cell_length_b 10.429
_cell_length_c 13.149
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 1238.536
_exptl_crystal_density_diffrn      2.808
_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
Na1   0.00000   0.00000   0.25050   0.60000   0.01900
Ca1   0.00000   0.00000   0.25050   0.40000   0.01900
Na2   0.50000   0.00000   0.00000   0.76000   0.02800
Na3   0.50000   0.00000   0.50000   0.60000   0.02300
Ca3   0.50000   0.00000   0.50000   0.40000   0.02300
Ca4   0.00000   0.00000   0.00000   1.00000   0.01200
Sil   0.15110  -0.15110   0.56420   1.00000   0.01400
Ol   0.25110   0.00000   0.50000   1.00000   0.05000
O2   0.11500  -0.11500   0.67400   1.00000   0.03400
O3   0.23850  -0.23850   0.55480   1.00000   0.03800