data_global
_chemical_name_mineral 'Combeite'
loop_
_publ_author_name
'Ohsato H'
'Maki I'
'Takeuchi Y'
_journal_name_full 'Acta Crystallographica, Section C'
_journal_volume 41 
_journal_year 1985
_journal_page_first 1575
_journal_page_last 1577
_publ_section_title
;
 Structure of Na2CaSi2O6
;
_database_code_amcsd 0010016
_chemical_compound_source 'synthetic high-temperature form'
_chemical_formula_sum 'Na2.914 Ca1.543 Si3 O9'
_cell_length_a 10.500
_cell_length_b 10.500
_cell_length_c 13.184
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 1258.799
_exptl_crystal_density_diffrn      2.827
_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   0.24850   0.70500   0.01317
Ca1   0.00000   0.00000   0.24850   0.29500   0.01317
Na2   0.50000   0.00000   0.00000   0.97200   0.03407
Na3   0.50000   0.00000   0.50000   0.50100   0.01697
Ca3   0.50000   0.00000   0.50000   0.49900   0.01697
Ca4   0.00000   0.00000   0.00000   1.00000   0.01026
Si   0.15020  -0.15020   0.56360   1.00000   0.00735
O1   0.25330   0.01310   0.51470   0.50000   0.03559
O2   0.11610  -0.11610   0.67340   1.00000   0.03394
O3   0.23730  -0.23730   0.55100   1.00000   0.03318