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: natural sample
 Note: T = 290 K
;
_database_code_amcsd 0006204
_chemical_compound_source 'Snipe River, Tambani, Malawi'
_chemical_formula_sum 'K.57 Na3.24 (Al3.84 Si4.16) O16'
_cell_length_a 9.9995
_cell_length_b 9.9995
_cell_length_c 8.3766
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 725.362
_exptl_crystal_density_diffrn      2.624
_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   0.00370   0.57000   0.03300
Na1   0.00000   0.00000   0.00370   0.24000   0.03300
Na2   0.55410   0.99720   0.50800   1.00000   0.02500
Al1   0.66667   0.33333   0.70150   0.48000   0.01300
Si1   0.66667   0.33333   0.70150   0.52000   0.01300
Al2   0.66667   0.33333   0.31320   0.48000   0.01400
Si2   0.66667   0.33333   0.31320   0.52000   0.01400
Al3   0.90570   0.66610   0.82240   0.48000   0.01400
Si3   0.90570   0.66610   0.82240   0.52000   0.01400
Al4   0.90640   0.66760   0.19590   0.48000   0.01200
Si4   0.90640   0.66760   0.19590   0.52000   0.01200
O1   0.66200   0.28910   0.50130   0.33333   0.03300
O2   0.97290   0.68350   0.00270   1.00000   0.03400
O3   0.82650   0.47750   0.25140   1.00000   0.03800
O4   0.83670   0.48980   0.76420   1.00000   0.03400
O5   0.77370   0.71470   0.82410   1.00000   0.02000
O6   0.77600   0.73290   0.20110   1.00000   0.02300