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 296
_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 90.0
_cell_angle_beta 90.0
_cell_angle_gamma 120.0
_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   0.9972  0.4432  0.9913  1.0
K   0.0  0.0  0.9893  1.0
Al1   0.333333  0.666667  0.1877  0.51
Si1   0.333333  0.666667  0.1877  0.49
Si2   0.333333  0.666667  0.799  0.58
Al2   0.333333  0.666667  0.799  0.42
Si3   0.0933  0.3344  0.309  0.84
Al3   0.0933  0.3344  0.309  0.16
Al4   0.0934  0.3318  0.6824  0.73
Si4   0.0934  0.3318  0.6824  0.27
O1   0.3327  0.7024  0.9846  0.333
O2   0.0269  0.3168  0.4921  1.0
O3   0.1713  0.5235  0.721  1.0
O4   0.1647  0.5108  0.2393  1.0
O5   0.2258  0.2873  0.3099  1.0
O6   0.2229  0.2657  0.6892  1.0
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  0.0011
K   0.03878  0.03878  0.03452  0.01939  0.0  0.0
Al1   0.01369  0.01369  0.01245  0.00684  0.0  0.0
Si1   0.01369  0.01369  0.01245  0.00684  0.0  0.0
Si2   0.02281  0.02281  0.01423  0.01141  0.0  0.0
Al2   0.02281  0.02281  0.01423  0.01141  0.0  0.0
Si3   0.00798  0.00874  0.01566  0.00342  -0.00331  -0.0011
Al3   0.00798  0.00874  0.01566  0.00342  -0.00331  -0.0011
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  0.0019  -0.00147  0.00589
O5   0.01407  0.02623  0.01032  0.01445  -0.00184  0.0
O6   0.02395  0.01673  0.02918  0.01445  -0.00405  0.0011