data_9007649
_chemical_name 'NaY9(SiO4)6O2'
loop_
_publ_author_name
'Gunawardane R P'
'Howie R A'
'Glasser F P'
_journal_name_full "Acta Crystallographica, Section B"
_journal_volume 38
_journal_year 1982
_journal_page_first 1564
_journal_page_last 1566
_publ_section_title
;
 Structure of the oxyapatite NaY9(SiO4)6O2
 Note: apatite structure
;
_chemical_formula_sum 'Na.5 Y4.5 Si3 O13'
_cell_length_a 9.334
_cell_length_b 9.334
_cell_length_c 6.759
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 509.975
_symmetry_space_group_name_H-M 'P 63/m'
loop_
_symmetry_equiv_pos_as_xyz
  'x,y,z'
  '-x+y,-x,1/2-z'
  'x-y,x,1/2+z'
  'y,-x+y,-z'
  '-y,x-y,z'
  'x,y,1/2-z'
  '-x,-y,1/2+z'
  'x-y,x,-z'
  '-x+y,-x,z'
  '-y,x-y,1/2-z'
  'y,-x+y,1/2+z'
  '-x,-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
_atom_site_Uiso_or_equiv
Na2   0.33333   0.66667  -0.00190   0.25000   0.00900
Y2   0.33333   0.66667  -0.00190   0.75000   0.00900
Y1   0.23750   0.00420   0.25000   1.00000   0.00894
Si   0.37230   0.39940   0.25000   1.00000   0.00329
O1   0.24860   0.33890   0.43800   1.00000   0.01507
O2   0.48680   0.31710   0.25000   1.00000   0.01241
O3   0.52520   0.40130   0.75000   1.00000   0.01051
O4   0.00000   0.00000   0.25000   1.00000   0.01520