#------------------------------------------------------------------------------
#$Date: 2009-11-14 15:09:05 +0200 (Sat, 14 Nov 2009) $
#$Revision: 846 $
#$URL: file:///home/coder/svn-repositories/cod/cif/2/2003129.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_2003129
_journal_name_full               'Acta Crystallographica, Section B'
_journal_volume                  55
_journal_year     1999
_journal_page_first     273
_journal_page_last     284
_publ_section_title
;
Electron Density Distribution and Madelung Potential in \a-Spodumene
 LiAl(SiO~3~)~2~ from Two Wavelengths High Resolution X-Ray Diffraction
 Data
;
loop_
    _publ_author_name
    'Kuntzinger, Sandrine'
    'Ghermani, Nour Eddine'
_chemical_formula_moiety     ?
_chemical_formula_sum     'Al Li O6 Si2'
_chemical_formula_iupac     'Li Al (Si O3)2'
_chemical_formula_weight     186.09
_symmetry_cell_setting     monoclinic
_symmetry_space_group_name_H-M     'C 1 2/c 1'
loop_
    _symmetry_equiv_pos_as_xyz
    'x, y, z'
    'x+1/2, y+1/2, z'
    '-x, y, -z+1/2'
    '-x+1/2, y+1/2, -z+1/2'
    '-x, -y, -z'
    'x, -y, z+1/2'
    '-x+1/2, -y+1/2, -z'
    'x+1/2, 1/2-y, z+1/2'
_cell_length_a     9.4620(10)
_cell_length_b     8.3920(10)
_cell_length_c     5.2210(10)
_cell_angle_alpha     90.00
_cell_angle_beta     110.180(10)
_cell_angle_gamma     90.00
_cell_volume     389.12(8)
_cell_formula_units_Z     4
_cell_measurement_reflns_used     25
_cell_measurement_theta_min     8.2
_cell_measurement_theta_max     22.5
_cell_measurement_temperature     293
_exptl_crystal_description     Parallelepiped
_exptl_crystal_colour     Colourless
_exptl_crystal_size_max     .36
_exptl_crystal_size_mid     .18
_exptl_crystal_size_min     .06
_exptl_crystal_size_rad     ?
_exptl_crystal_density_diffrn     3.18
_exptl_crystal_density_meas     ?
_exptl_crystal_density_method     'not measured'
_exptl_crystal_F_000     368.0
_exptl_absorpt_coefficient_mu     1.05
loop_
    _exptl_absorpt_correction_type
    _exptl_absorpt_process_details
    integration '(ABSORB, G. de Titta, 1985)'
    empirical '(DREADD, R. Blessing, 1995)'
_exptl_absorpt_correction_T_min     .68
_exptl_absorpt_correction_T_max     .95
_diffrn_radiation_type     'Mo K\a'
_diffrn_radiation_wavelength     .7107
_diffrn_measurement_device     'Enraf-Nonius CAD4 diffractometer'
_diffrn_measurement_method     '\w/2\q scans'
_diffrn_detector_area_resol_mean     ?
_diffrn_reflns_number     12984
_diffrn_reflns_av_R_equivalents     0.0210
_diffrn_reflns_theta_min     3.3
_diffrn_reflns_theta_max     60.12
_diffrn_reflns_theta_full     50.0
_diffrn_measured_fraction_theta_max     .95
_diffrn_measured_fraction_theta_full     .98
_diffrn_reflns_limit_h_min     -22
_diffrn_reflns_limit_h_max     22
_diffrn_reflns_limit_k_min     -18
_diffrn_reflns_limit_k_max     20
_diffrn_reflns_limit_l_min     -12
_diffrn_reflns_limit_l_max     11
_diffrn_standards_number     3
_diffrn_standards_interval_time     120
_diffrn_standards_decay_%     0
_reflns_number_total     2945
_reflns_number_gt     2366
_reflns_threshold_expression     I>3\s(I)
_refine_ls_structure_factor_coef     F
_refine_ls_R_factor_gt     .0137
_refine_ls_wR_factor_ref     .0145
_refine_ls_goodness_of_fit_ref     .97
_refine_ls_number_reflns     2366
_refine_ls_number_parameters     138
_refine_ls_weighting_scheme     calc
_refine_ls_weighting_details     'w=1/[\s^2^(F^2^)+(0.0130F^2^)^2^]'
_refine_ls_shift/su_max     0.0
_refine_diff_density_max     0.3
_refine_diff_density_min     -0.1
loop_
    _refine_ls_extinction_method
    'Becker-Coppens type 1 Lorentzian isotropic'
_refine_ls_extinction_coef     5.0x10^2^
_refine_ls_abs_structure_details     ?
_refine_ls_abs_structure_Flack     ?
loop_
    _atom_type_symbol
    _atom_type_description
    _atom_type_scat_dispersion_real
    _atom_type_scat_dispersion_imag
    _atom_type_scat_source
    'Si' 'Si' .0817 .0704
                         'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
    'Al' 'Al' .0645 .0514
                         'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
    'O' 'O' .0106 .0060 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
    'Li' 'Li' -.0003 .0001
                         'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
loop_
    _atom_site_label
    _atom_site_fract_x
    _atom_site_fract_y
    _atom_site_fract_z
    _atom_site_U_iso_or_equiv
    _atom_site_thermal_displace_type
    _atom_site_type_symbol
    Si 0.294100(10)
                  0.093470(10)
                             0.255920(10)
                                        0.00377(2) Uani Si
    Al 0.00000 0.906670(10)
                          0.25000 0.00409(2) Uani Al
    O~1~ 0.10971(2) 0.08232(2) 0.14056(4) 0.00479(4) Uani O
    O~2~ 0.36470(2) 0.26713(2) 0.30048(4) 0.00758(5) Uani O
    O~3~ 0.35663(2) 0.98674(3) 0.05827(4) 0.00749(5) Uani O
    Li 0.00000 0.27467(13) 0.25000 0.0146(4) Uani Li
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
    Si 0.00360(2) 0.00432(2) 0.00332(2) -0.00061(2) 0.00109(2) -0.00019(2)
    Al 0.00407(3) 0.00419(3) 0.00393(3) 0.00000 0.00126(3) 0.00000
    O~1~ 0.00368(4) 0.00563(5) 0.00463(5) -0.00036(4) 0.00090(4) 0.00013(4)
    O~2~ 0.00799(6) 0.00560(5) 0.00983(6) -0.00293(4) 0.00393(5) -0.00098(5)
    O~3~ 0.00572(5) 0.01129(6) 0.00508(5) 0.00067(5) 0.00139(4) -0.00337(5)
    Li 0.0146(4)   0.0139(4)   0.0159(4)   0.00000 0.0058(3)   0.00000