Structure of russellite (Bi~2~WO~6~): origin of ferroelectricity and the effect of the stereoactive lone electron pair on the structure
Okudera, Hiroki; Sakai, Yuka; Yamagata, Kentaro; Takeda, Hiroaki; Acta Crystallographica Section B 74 (2018) 295–303; doi:10.1107/S2052520618006133

data_2108252
_publ_section_title
;
 Structure of russellite (Bi~2~WO~6~): origin of ferroelectricity and the
 effect of the stereoactive lone electron pair on the structure
;
_journal_coeditor_code           LO5019SUP1
_journal_issue                   3
_journal_name_full               'Acta Crystallographica Section B'
_journal_page_first              295
_journal_page_last               303
_journal_paper_doi               10.1107/S2052520618006133
_journal_volume                  74
_journal_year                    2018
_chemical_compound_source        Synthetic
_chemical_formula_iupac          'Bi2 W O6'
_chemical_formula_structural     'Bi2 O2 (W O4)'
_chemical_formula_sum            'Bi2 O6 W'
_chemical_formula_weight         697.797
_chemical_name_common            'Bismuth tungstate'
_space_group_IT_number           29
_space_group_name_H-M_alt        'P c a 21'
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'P 2c -2ac'
_symmetry_space_group_name_H-M   'P c a 21'
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   5.4345(12)
_cell_length_b                   16.4324(12)
_cell_length_c                   5.4558(12)
_cell_measurement_reflns_used    16
_cell_measurement_temperature    296
_cell_measurement_theta_max      53
_cell_measurement_theta_min      40
_cell_volume                     487.21(16)
_computing_cell_refinement       'Rigaku Control software, corrected with Si'
_computing_data_collection       'AFC-5S control'
_computing_data_reduction        'AFCPHI, SORT6 (parts of LSGCEX)'
_computing_molecular_graphics    'VESTA (Momma & Izumi, 2008)'
_computing_publication_material  none
_computing_structure_refinement  'LSGCEX (Kihara, 1990)'
_diffrn_ambient_temperature      296
_diffrn_measured_fraction_theta_full 1.0
_diffrn_measured_fraction_theta_max 1.0
_diffrn_measurement_device_type  'Rigaku AFC5S diffractometer'
_diffrn_measurement_method       'integrated with \v/2\q scans'
_diffrn_radiation_monochromator  'graphite (002)'
_diffrn_radiation_source         'X-ray tube, 50kV 25mA'
_diffrn_radiation_type           Mo-K\a
_diffrn_radiation_wavelength     0.71069
_diffrn_reflns_av_R_equivalents  0.0377
_diffrn_reflns_limit_h_max       8
_diffrn_reflns_limit_h_min       -8
_diffrn_reflns_limit_k_max       26
_diffrn_reflns_limit_k_min       -26
_diffrn_reflns_limit_l_max       8
_diffrn_reflns_limit_l_min       -8
_diffrn_reflns_number            8160
_diffrn_reflns_theta_full        35.02
_diffrn_reflns_theta_max         35.02
_diffrn_reflns_theta_min         4.00
_diffrn_standards_decay_%        0
_diffrn_standards_interval_count 200
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    95.558
_exptl_absorpt_correction_T_max  0.0052
_exptl_absorpt_correction_T_min  0.0037
_exptl_absorpt_correction_type   sphere
_exptl_absorpt_process_details   'spherical absorption correction'
_exptl_crystal_colour            'pale yellow'
_exptl_crystal_density_diffrn    9.513
_exptl_crystal_description       sphere
_exptl_crystal_F_000             1152
_exptl_crystal_size_max          0.104
_exptl_crystal_size_mid          0.104
_exptl_crystal_size_min          0.104
_exptl_crystal_size_rad          0.052
_pd_phase_name                   Russellite-OR-3-final
_refine_diff_density_max         3.18
_refine_diff_density_min         -2.76
_refine_ls_extinction_coef       0.022173(1262)
_refine_ls_extinction_method     'B-C type 1 Lorenzian isotropic'
_refine_ls_goodness_of_fit_ref   0.5164
_refine_ls_matrix_type           full
_refine_ls_number_constraints    5
_refine_ls_number_parameters     42
_refine_ls_number_reflns         784
_refine_ls_number_restraints     9
_refine_ls_R_factor_gt           0.0168
_refine_ls_structure_factor_coef F
_refine_ls_weighting_details     'weight proportional to sigma^-2^'
_refine_ls_weighting_scheme      sigma
_refine_ls_wR_factor_ref         0.0204
_reflns_number_gt                844
_reflns_number_total             2163
_reflns_observed_criterion       F>3u(F)
_reflns_threshold_expression
'F>3u(F) & (|Fobs.max|-|Fobs.min|)/|Fobs.min| < 0.5 among equivalents'
_cod_data_source_file            lo5019sup1.cif
_cod_data_source_block           I
_cod_database_code               2108252
_cod_database_fobs_code 2108252