#------------------------------------------------------------------------------
#$Date: 2008-01-13 23:15:36 +0100 (Sun, 13 Jan 2008) $
#$Revision: 14 $
#$URL: svn://www.crystallography.net/cod/cif/2/2003027.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_2003027
_journal_name_full     'Acta Crystallographica, Section B'
_journal_year     1998
_journal_volume     B54
_journal_page_first     568
_journal_page_last     577
_chemical_name_systematic
;
 Lithium Disilicate
;
_chemical_formula_moiety     'Li2 Si2 O5'
_chemical_formula_sum     'Li2 O5 Si2'
_chemical_formula_weight     150.05
_symmetry_cell_setting     Orthorhombic
_symmetry_space_group_name_H-M     'C c c 2'
_symmetry_space_group_name_Hall     'C 2 -c'
loop_
    _symmetry_equiv_pos_as_xyz
    x,y,z
    -x,y,1/2+z
    x,-y,1/2+z
    -x,-y,z
    1/2+x,1/2+y,z
    1/2-x,1/2+y,1/2+z
    1/2+x,1/2-y,1/2+z
    1/2-x,1/2-y,z
_cell_length_a     5.807(2)
_cell_length_b     14.582(7)
_cell_length_c     4.773(3)
_cell_angle_alpha     90
_cell_angle_beta     90
_cell_angle_gamma     90
_cell_volume     404.2(3)
_cell_formula_units_Z     4
_cell_measurement_reflns_used     10
_cell_measurement_theta_min     11
_cell_measurement_theta_max     13
_cell_measurement_temperature     293
_exptl_crystal_description     'thin plate'
_exptl_crystal_colour     'colorless'
_exptl_crystal_size_max     0.50
_exptl_crystal_size_mid     0.15
_exptl_crystal_size_min     0.012
_exptl_crystal_density_diffrn     2.466
_exptl_crystal_density_meas     'Not measured'
_exptl_crystal_F_000     296
_exptl_absorpt_coefficient_mu     0.78
_exptl_absorpt_correction_type     'analytical (Spek, 1990)'
_exptl_absorpt_process_details     'de Meulenaar & Tompa'
_exptl_absorpt_correction_T_min     0.789
_exptl_absorpt_correction_T_max     0.991
_diffrn_ambient_temperature     293
_diffrn_radiation_type     'Mo K\a'
_diffrn_radiation_wavelength     0.71073
_diffrn_radiation_source     'Rotating Anode'
_diffrn_radiation_monochromator     'graphite'
_diffrn_measurement_device_type     'CAD4-T'
_diffrn_measurement_method     '\w-2\q-scan'
_diffrn_reflns_number     967
_diffrn_reflns_av_R_equivalents     0.0639
_diffrn_reflns_av_sigmaI/netI     0.0383
_diffrn_reflns_theta_min     2.79
_diffrn_reflns_theta_max     27.46
_diffrn_reflns_limit_h_min     -7
_diffrn_reflns_limit_h_max     7
_diffrn_reflns_limit_k_min     -18
_diffrn_reflns_limit_k_max     18
_diffrn_reflns_limit_l_min     0
_diffrn_reflns_limit_l_max     6
_diffrn_standards_number     1
_diffrn_standards_interval_time     60
_diffrn_standards_decay_%     1
_reflns_number_total     261
_reflns_number_gt     249
_reflns_threshold_expression     'I > 2 \s(I)'
_refine_ls_structure_factor_coef     Fsqd
_refine_ls_matrix_type     full
_refine_ls_R_factor_all     0.0464
_refine_ls_R_factor_gt     0.0450
_refine_ls_wR_factor_ref     0.1138
_refine_ls_goodness_of_fit_ref     1.133
_refine_ls_restrained_S_all     1.130
_refine_ls_number_reflns     261
_refine_ls_number_parameters     42
_refine_ls_number_restraints     1
_refine_ls_hydrogen_treatment     'H-atom refinement: see text '
_refine_ls_weighting_scheme
            'w = 1/[\s^2^(Fo^2^)+(0.0883P)^2^+0.0491P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_shift/su_max     0.000
_refine_ls_shift/su_mean     0.000
_refine_diff_density_max     0.818
_refine_diff_density_min     -0.579
_refine_ls_extinction_method     none
loop_
    _atom_type_symbol
    _atom_type_description
    _atom_type_scat_dispersion_real
    _atom_type_scat_dispersion_imag
    _atom_type_scat_source
    Si Si 0.0817 0.0704 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
    O O 0.0106 0.0060 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
    Li Li -0.0003 0.0001 '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_occupancy
    Si 0.34480(18) 0.85156(7) 0.50757(16) 0.0071(4) Uani 1.000
    O1 0.1703(6) 0.9278(2) 0.5978(11) 0.0105(9) Uani 1.000
    O2 0.5924(7) 0.8623(2) 0.6716(9) 0.0105(9) Uani 1.000
    O3 0.25000 0.75000 0.5639(12) 0.0136(13) Uani 1.000
    Li 0.8484(13) 0.9418(5) 0.510(3) 0.0150(19) Uani 1.000
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 0.0058(7) 0.0092(7) 0.0064(7) 0.0002(3) 0.0007(5) 0.0002(6)
    O1 0.0097(15) 0.0127(15) 0.0090(17) 0.0026(11) 0.0009(11) -0.0013(12)
    O2 0.0064(15) 0.0172(16) 0.0080(18) -0.0005(12) -0.0012(16) 0.0006(13)
    O3 0.016(2) 0.0088(18) 0.016(3) -0.0031(18) 0.0000 0.0000
    Li 0.012(3) 0.014(3) 0.019(4) -0.005(3) -0.001(4) 0.002(5)