Crystal Structure and Oxide-Ion Conductivity alongc-Axis of Apatite-Type Lanthanum Silicate with Excess Oxide Ions
Fukuda, Koichiro; Asaka, Toru; Oyabu, Masayuki; Urushihara, Daisuke; Berghout, Abid; Béchade, Emilie; Masson, Olivier; Julien, Isabelle; Thomas, Philippe; Chemistry of Materials 24 (2012) 4623–; doi:10.1021/cm3034643

data_4001712
_publ_section_title
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 Crystal Structure and Oxide-Ion Conductivity alongc-Axis of Apatite-Type
 Lanthanum Silicate with Excess Oxide Ions
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_journal_issue                   23
_journal_name_full               'Chemistry of Materials'
_journal_page_first              4623
_journal_paper_doi               10.1021/cm3034643
_journal_volume                  24
_journal_year                    2012
_chemical_formula_moiety         'La9.50 O26.26 Si6'
_chemical_formula_sum            'La9.5 O26.26 Si6'
_chemical_formula_weight         1908.87
_chemical_name_systematic        ' ?'
_space_group_IT_number           176
_symmetry_cell_setting           hexagonal
_symmetry_Int_Tables_number      176
_symmetry_space_group_name_Hall  '-P 6c'
_symmetry_space_group_name_H-M   'P 63/m'
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                120
_cell_formula_units_Z            1
_cell_length_a                   9.7136(1)
_cell_length_b                   9.7136(1)
_cell_length_c                   7.1814(1)
_cell_measurement_temperature    293
_cell_volume                     586.814(12)
_diffrn_ambient_temperature      293
_diffrn_measured_fraction_theta_full 0.99
_diffrn_measured_fraction_theta_max 0.99
_diffrn_measurement_device_type  'Bruker APEXII CCD'
_diffrn_measurement_method       '\f and \w'
_diffrn_radiation_source         'X-ray tube'
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0357
_diffrn_reflns_av_sigmaI/netI    0.0299
_diffrn_reflns_limit_h_max       19
_diffrn_reflns_limit_h_min       -19
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -18
_diffrn_reflns_limit_l_max       14
_diffrn_reflns_limit_l_min       -5
_diffrn_reflns_number            10770
_diffrn_reflns_theta_full        47.75
_diffrn_reflns_theta_max         47.75
_diffrn_reflns_theta_min         2.42
_exptl_absorpt_coefficient_mu    17.306
_exptl_absorpt_correction_T_max  0.844
_exptl_absorpt_correction_T_min  0.607
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '(SADABS; Sheldrick, 1996)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    5.402
_exptl_crystal_description       prism
_exptl_crystal_F_000             836
_exptl_crystal_size_max          0.02
_exptl_crystal_size_mid          0.015
_exptl_crystal_size_min          0.010
_refine_diff_density_max         1.13
_refine_diff_density_min         -1.33
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_gt    1.09
_refine_ls_goodness_of_fit_ref   1.02
_refine_ls_number_constraints    1
_refine_ls_number_parameters     80
_refine_ls_number_reflns         1943
_refine_ls_number_restraints     0
_refine_ls_R_factor_all          0.0412
_refine_ls_R_factor_gt           0.0204
_refine_ls_shift/su_max          0.0482
_refine_ls_shift/su_mean         0.0036
_refine_ls_structure_factor_coef F
_refine_ls_weighting_details     w=1/(\s^2^(F)+0.0001F^2^)
_refine_ls_weighting_scheme      sigma
_refine_ls_wR_factor_gt          0.0202
_refine_ls_wR_factor_ref         0.0226
_reflns_number_gt                1373
_reflns_number_total             1943
_reflns_threshold_expression     I>3\s(I)
_cod_data_source_file            cm3034643_si_003.cif
_cod_data_source_block           I
_cod_original_cell_volume        586.81(1)
_cod_original_formula_sum        'La9.50 O26.26 Si6'
_cod_database_code               4001712
_atom_site_anharm_details
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The atomic anharmonic pdf is approximated by a Gram-Charlier expansion
about the harmonic pdf, according to the expression :

      P(u) = (1 + Cijk*Hijk/3! + Dijkl*Hijkl/4!)*P(0)

The coefficients Cijk and Dijkl are refined in the least squares procedure.
The reported coefficients Cijk are multiplied by 1000 and Dijkl by 10000.
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