data_global
_chemical_name_mineral 'Nepheline'
loop_
_publ_author_name
'Angel R J'
'Gatta G C'
'Boffa Ballaran T'
'Carpenter M A'
_journal_name_full 'The Canadian Mineralogist'
_journal_volume 46 
_journal_year 2008
_journal_page_first 1465
_journal_page_last 1476
_publ_section_title
;
 The mechanism of coupling in the modulated structure of nepheline
 Note: annealed
 Note: T = 220 K
;
_database_code_amcsd 0006205
_chemical_compound_source 'Snipe River, Tambani, Malawi'
_chemical_formula_sum 'K.57 Na3.24 (Al3.84 Si4.16) O16'
_cell_length_a 9.9751
_cell_length_b 9.9751
_cell_length_c 8.3658
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 720.896
_exptl_crystal_density_diffrn      2.641
_symmetry_space_group_name_H-M 'P 63'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  'x-y,x,1/2+z'
  '-y,x-y,z'
  '-x,-y,1/2+z'
  '-x+y,-x,z'
  'y,-x+y,1/2+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
K   0.00000   0.00000   0.00310   0.57000   0.02800
Na1   0.00000   0.00000   0.00310   0.24000   0.02800
Na2   0.55470   0.99790   0.50810   1.00000   0.02000
Al1   0.66667   0.33333   0.70170   0.48000   0.01100
Si1   0.66667   0.33333   0.70170   0.52000   0.01100
Al2   0.66667   0.33333   0.31240   0.48000   0.01200
Si2   0.66667   0.33333   0.31240   0.52000   0.01200
Al3   0.90660   0.66640   0.82260   0.48000   0.01100
Si3   0.90660   0.66640   0.82260   0.52000   0.01100
Al4   0.90710   0.66790   0.19580   0.48000   0.01000
Si4   0.90710   0.66790   0.19580   0.52000   0.01000
O1   0.66400   0.29100   0.50230   0.33333   0.02800
O2   0.97430   0.68420   0.00220   1.00000   0.02800
O3   0.82720   0.47730   0.25120   1.00000   0.03300
O4   0.83730   0.48960   0.76450   1.00000   0.02900
O5   0.77390   0.71450   0.82520   1.00000   0.01600
O6   0.77670   0.73350   0.20070   1.00000   0.01800