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 = 110 K
;
_database_code_amcsd 0006202
_chemical_compound_source 'Snipe River, Tambani, Malawi'
_chemical_formula_sum 'K.57 Na3.24 (Al3.84 Si4.16) O16'
_cell_length_a 9.9820
_cell_length_b 9.9820
_cell_length_c 8.3670
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 721.997
_exptl_crystal_density_diffrn      2.637
_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   0.02400
Na1   0.00000   0.00000   0.00310   0.24000   0.02400
Na2   0.55470   0.99710   0.50820   1.00000   0.01700
Al1   0.66667   0.33333   0.70140   0.48000   0.01000
Si1   0.66667   0.33333   0.70140   0.52000   0.01000
Al2   0.66667   0.33333   0.31370   0.48000   0.01200
Si2   0.66667   0.33333   0.31370   0.52000   0.01200
Al3   0.90640   0.66600   0.82220   0.48000   0.01200
Si3   0.90640   0.66600   0.82220   0.52000   0.01200
Al4   0.90710   0.66720   0.19590   0.48000   0.01000
Si4   0.90710   0.66720   0.19590   0.52000   0.01000
O1   0.66110   0.28250   0.50050   0.33333   0.02400
O2   0.97340   0.68220   0.00220   1.00000   0.03400
O3   0.82700   0.47740   0.25180   1.00000   0.03800
O4   0.83740   0.48910   0.76130   1.00000   0.03200
O5   0.77360   0.71430   0.82530   1.00000   0.01600
O6   0.77650   0.73290   0.20120   1.00000   0.01800