#------------------------------------------------------------------------------
#$Date: 2008-01-13 22:15:36 +0000 (Sun, 13 Jan 2008) $
#$Revision: 14 $
#$URL: svn://www.crystallography.net/cod/cif/2/2002898.cif $
#------------------------------------------------------------------------------
#
# This file is available in the Crystallography Open Database (COD),
# http://www.crystallography.net/
#
# All data on this site have been placed in the public domain by the
# contributors.
#
data_2002898
_journal_name_full     'Acta Crystallographica, Section B'
_journal_year     1998
_journal_volume     B54
_journal_page_first     547
_journal_page_last     557
_publ_section_title
;
Cristobalite-related phases in the NaAlO2-NaAlSiO4 system  II.
A commensurately modulated cubic structure
;
loop_
    _publ_author_name
    'Withers, Ray L.'
    'Thompson, John G.'
    'Melnitchenko, Alexandra'
    'Palethorpe, Stephen R.'
_chemical_formula_sum     'Na1.45 Al1.45 Si0.55 O4'
_chemical_formula_weight     151.90
_symmetry_space_group_name_H-M     'P 21 3'
loop_
    _symmetry_equiv_pos_as_xyz
    'x,y,z'
    '1/2-x,-y,1/2+z'
    '-x,1/2+y,1/2-z'
    '1/2+x,1/2-y,-z'
    'z,x,y'
    '1/2+z,1/2-x,-y'
    '1/2-z,-x,1/2+y'
    '-z,1/2+x,1/2-y'
    'y,z,x'
    '-y,1/2+z,1/2-x'
    '1/2+y,1/2-z,-x'
    '1/2-y,-z,1/2+x'
_cell_length_a     14.5530(10)
_cell_length_b     14.5530(10)
_cell_length_c     14.5530(10)
_cell_angle_alpha     90.0
_cell_angle_beta     90.0
_cell_angle_gamma     90.0
_cell_volume     3082.0(6)
_cell_formula_units_Z     32
_cell_measurement_temperature     293
_exptl_crystal_density_diffrn     2.619
_exptl_absorpt_correction_T_min     ?
_exptl_absorpt_correction_T_max     ?
_diffrn_ambient_temperature     293
_diffrn_radiation_type     'Cu K\a'
_diffrn_radiation_wavelength     1.5418
_diffrn_radiation_source     'sealed tube'
_diffrn_radiation_monochromator     'graphite'
_diffrn_measurement_device     'Siemens D-5000'
_diffrn_measurement_method     'profile data from theta/2theta scan'
loop_
    _atom_site_label
    _atom_site_fract_x
    _atom_site_fract_y
    _atom_site_fract_z
    _atom_site_U_iso_or_equiv
    _atom_site_occupancy
    _atom_site_type_symbol
    M1 0.0132 0.0132 0.0132 0.000(4) 0.725 Al
    M1 0.0132 0.0132 0.0132 0.000(4) 0.275 Si
    M2 0.1498 0.1498 0.1498 0.000(4) 0.725 Al
    M2 0.1498 0.1498 0.1498 0.000(4) 0.275 Si
    M3 0.4572 0.4572 0.4572 0.000(4) 0.725 Al
    M3 0.4572 0.4572 0.4572 0.000(4) 0.275 Si
    M4 0.6118 0.6118 0.6118 0.000(4) 0.725 Al
    M4 0.6118 0.6118 0.6118 0.000(4) 0.275 Si
    M5 -0.0143 0.2476 0.2422 0.000(4) 0.725 Al
    M5 -0.0143 0.2476 0.2422 0.000(4) 0.275 Si
    M6 0.0190 0.7880 0.7500 0.000(4) 0.725 Al
    M6 0.0190 0.7880 0.7500 0.000(4) 0.275 Si
    M7 0.3618 0.6118 0.3618 0.000(4) 0.725 Al
    M7 0.3618 0.6118 0.3618 0.000(4) 0.275 Si
    M8 0.8998 0.1498 0.8998 0.000(4) 0.725 Al
    M8 0.8998 0.1498 0.8998 0.000(4) 0.275 Si
    Na1 0.2640(10)
                 0.2640(10)
                          0.2640(10)
                                   0.053(9) 0.725 Na
    Na2 0.375 0.375 0.375 - 0.0 Na
    Na3 0.7360(10)
                 0.7360(10)
                          0.7360(10)
                                   0.053(9) 0.725 Na
    Na4 0.875 0.875 0.875 - 0.0 Na
    Na5 0.231(3) 0.488(3) 0.484(3) 0.053(9) 1.21 Na
    Na6 0.250 0.000 0.000 0.053(9) 0.24 Na
    Na7 0.121(4) 0.371(5) 0.097(2) 0.053(9) 0.967 Na
    Na8 0.644(3) 0.867(4) 0.639(4) 0.053(9) 0.967 Na
    O1 0.0815 0.0815 0.0815 0.038(8) 1.0 O
    O2 0.0815 -0.0815 -0.0055 0.038(8) 1.0 O
    O3 0.5435 0.5435 0.5435 0.038(8) 1.0 O
    O4 0.5435 0.4565 0.3805 0.038(8) 1.0 O
    O5 0.4185 0.1685 0.3315 0.038(8) 1.0 O
    O6 -0.0435 0.7065 0.7935 0.038(8) 1.0 O
    O7 0.2445 0.0815 0.1685 0.038(8) 1.0 O
    O8 0.6305 0.5435 0.7065 0.038(8) 1.0 O
    O9 0.0055 0.3315 0.3315 0.038(8) 1.0 O
    O10 0.0815 0.7445 0.6685 0.038(8) 1.0 O
    O11 -0.1195 0.2065 0.2935 0.038(8) 1.0 O
    O12 -0.0435 0.8695 0.7065 0.038(8) 1.0 O