data_global
_amcsd_formula_title 'Si3N4'
loop_
_publ_author_name
'Yang P'
'Fun H-K'
'Rahman I A'
'Saleh M I'
_journal_name_full 'Ceramics International'
_journal_volume 21 
_journal_year 1995
_journal_page_first 137
_journal_page_last 142
_publ_section_title
;
 Two phase refinements of the structures of a-Si3N4 and B-Si3N4 made from rice
 husk by Rietveld analysis
 Sample: Beta phase
;
_database_code_amcsd 0012186
_chemical_formula_sum 'Si3 N4'
_cell_length_a 7.6093
_cell_length_b 7.6093
_cell_length_c 2.9079
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 145.814
_exptl_crystal_density_diffrn      3.195
_symmetry_space_group_name_H-M 'P 63/m'
loop_
_space_group_symop_operation_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_U_iso_or_equiv
Si   0.17420  -0.23220   0.25000   0.00646
N1   0.33333   0.66667   0.25000   0.01140
N2   0.32900   0.03900   0.25000   0.02533