data_global
_chemical_name_mineral 'Nepheline'
loop_
_publ_author_name
'Simmons W B'
'Peacor D R'
_journal_name_full 'American Mineralogist'
_journal_volume 57 
_journal_year 1972
_journal_page_first 1711
_journal_page_last 1719
_publ_section_title
;
 Refinement of the crystal structure of a volcanic nepheline
;
_database_code_amcsd 0000296
_chemical_formula_sum 'Na3 K (Al3.6 Si4.4) O15.999'
_cell_length_a 10.003
_cell_length_b 10.003
_cell_length_c 8.381
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 726.251
_exptl_crystal_density_diffrn      2.674
_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
Na   0.99720   0.44320   0.99130   1.00000
K   0.00000   0.00000   0.98930   1.00000
Al1   0.33330   0.66670   0.18770   0.51000
Si1   0.33330   0.66670   0.18770   0.49000
Si2   0.33330   0.66670   0.79900   0.58000
Al2   0.33330   0.66670   0.79900   0.42000
Si3   0.09330   0.33440   0.30900   0.84000
Al3   0.09330   0.33440   0.30900   0.16000
Al4   0.09340   0.33180   0.68240   0.73000
Si4   0.09340   0.33180   0.68240   0.27000
O1   0.33270   0.70240   0.98460   0.33300
O2   0.02690   0.31680   0.49210   1.00000
O3   0.17130   0.52350   0.72100   1.00000
O4   0.16470   0.51080   0.23930   1.00000
O5   0.22580   0.28730   0.30990   1.00000
O6   0.22290   0.26570   0.68920   1.00000
loop_
_atom_site_aniso_label
_atom_site_aniso_U_11
_atom_site_aniso_U_22
_atom_site_aniso_U_33
_atom_site_aniso_U_12
_atom_site_aniso_U_13
_atom_site_aniso_U_23
Na 0.03117 0.01901 0.01922 0.01217 0.00147 0.00110
K 0.03878 0.03878 0.03452 0.01939 0.00000 0.00000
Al1 0.01369 0.01369 0.01245 0.00684 0.00000 0.00000
Si1 0.01369 0.01369 0.01245 0.00684 0.00000 0.00000
Si2 0.02281 0.02281 0.01423 0.01141 0.00000 0.00000
Al2 0.02281 0.02281 0.01423 0.01141 0.00000 0.00000
Si3 0.00798 0.00874 0.01566 0.00342 -0.00331 -0.00110
Al3 0.00798 0.00874 0.01566 0.00342 -0.00331 -0.00110
Al4 0.01026 0.01255 0.00961 0.00608 -0.00441 -0.00184
Si4 0.01026 0.01255 0.00961 0.00608 -0.00441 -0.00184
O1 0.04296 0.03003 0.03736 0.03079 -0.03053 -0.02501
O2 0.02357 0.04562 0.01566 0.02319 -0.00772 -0.00662
O3 0.02509 0.02167 0.06512 0.01331 0.00037 0.00809
O4 0.00836 0.00836 0.03665 0.00190 -0.00147 0.00589
O5 0.01407 0.02623 0.01032 0.01445 -0.00184 0.00000
O6 0.02395 0.01673 0.02918 0.01445 -0.00405 0.00110