Confinement-Driven Ferroelectricity in a Two-Dimensional Hybrid Lead Iodide Perovskite.
Chen, Xiao-Gang; Song, Xian-Jiang; Zhang, Zhi-Xu; Zhang, Han-Yue; Pan, Qiang; Yao, Jie; You, Yu-Meng; Xiong, Ren-Gen; Journal of the American Chemical Society 142 (2020) 10212–10218; doi:10.1021/jacs.0c03710

data_4134992
_publ_section_title
;
 Confinement-Driven Ferroelectricity in a Two-Dimensional Hybrid Lead
 Iodide Perovskite.
;
_journal_issue                   22
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              10212
_journal_page_last               10218
_journal_paper_doi               10.1021/jacs.0c03710
_journal_volume                  142
_journal_year                    2020
_chemical_formula_moiety         'I4 Pb, 2(C6 H12 F2 N) '
_chemical_formula_sum            'C12 H24 F4 I4 N2 Pb'
_chemical_formula_weight         987.13
_space_group_crystal_system      orthorhombic
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_space_group_name_Hall           'C 2c -2'
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_cell_angle_beta                 90
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_cell_length_a                   8.5418(6)
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_cell_length_c                   10.0432(6)
_cell_measurement_reflns_used    3198
_cell_measurement_temperature    343(2)
_cell_measurement_theta_max      29.5520
_cell_measurement_theta_min      2.5500
_cell_volume                     2302.2(3)
_computing_structure_refinement  'SHELXL-2014/7 (Sheldrick, 2014)'
_diffrn_ambient_temperature      343(2)
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.816
_diffrn_measurement_device_type  'XtaLAB Synergy R, DW system, HyPix'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0996
_diffrn_reflns_av_unetI/netI     0.0598
_diffrn_reflns_Laue_measured_fraction_full 0.998
_diffrn_reflns_Laue_measured_fraction_max 0.816
_diffrn_reflns_limit_h_max       12
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_diffrn_reflns_limit_k_max       38
_diffrn_reflns_limit_k_min       -33
_diffrn_reflns_limit_l_max       12
_diffrn_reflns_limit_l_min       -14
_diffrn_reflns_number            5458
_diffrn_reflns_point_group_measured_fraction_full 0.999
_diffrn_reflns_point_group_measured_fraction_max 0.814
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_diffrn_reflns_theta_max         30.646
_diffrn_reflns_theta_min         2.502
_diffrn_source                   'Rotating-anode X-ray tube'
_exptl_absorpt_coefficient_mu    12.721
_exptl_absorpt_correction_T_max  0.101
_exptl_absorpt_correction_T_min  0.076
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
CrysAlisPro 1.171.40.14e (Rigaku Oxford Diffraction, 2018)
Empirical absorption correction using spherical harmonics,
 implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            red
_exptl_crystal_density_diffrn    2.848
_exptl_crystal_description       sheet
_exptl_crystal_F_000             1760
_exptl_crystal_size_max          0.22
_exptl_crystal_size_mid          0.20
_exptl_crystal_size_min          0.18
_refine_diff_density_max         2.263
_refine_diff_density_min         -2.140
_refine_diff_density_rms         0.314
_refine_ls_abs_structure_details
;
 Refined as an inversion twin.
;
_refine_ls_abs_structure_Flack   0.232(9)
_refine_ls_extinction_coef       0.00048(7)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     'SHELXL-2014/7 (Sheldrick 2014'
_refine_ls_goodness_of_fit_ref   1.065
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     150
_refine_ls_number_reflns         3529
_refine_ls_number_restraints     149
_refine_ls_restrained_S_all      1.044
_refine_ls_R_factor_all          0.0842
_refine_ls_R_factor_gt           0.0706
_refine_ls_shift/su_max          0.021
_refine_ls_shift/su_mean         0.002
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.1326P)^2^+34.6830P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.2083
_refine_ls_wR_factor_ref         0.2233
_reflns_Friedel_coverage         0.896
_reflns_Friedel_fraction_full    1.000
_reflns_Friedel_fraction_max     0.812
_reflns_number_gt                1895
_reflns_number_total             3529
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            ja0c03710_si_008.cif
_cod_data_source_block           CMC21
_cod_depositor_comments
;Adding full bibliography for 4134988--4134996.cif.

 Adding full bibliography for 4134988--4134996.cif.
;
_cod_database_code               4134992
_shelx_shelxl_version_number     2014/7
_shelx_res_checksum              79140
_shelx_hkl_checksum              70976