Discovery of an Above-Room-Temperature Antiferroelectric in Two-Dimensional Hybrid Perovskite.
Wu, Zhenyue; Liu, Xitao; Ji, Chengmin; Li, Lina; Wang, Sasa; Peng, Yu; Tao, Kewen; Sun, Zhihua; Hong, Maochun; Luo, Junhua; Journal of the American Chemical Society 141 (2019) 3812–3816; doi:10.1021/jacs.8b13827

data_4128537
_publ_section_title
;
 Discovery of an Above-Room-Temperature Antiferroelectric in
 Two-Dimensional Hybrid Perovskite.
;
_journal_issue                   9
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              3812
_journal_page_last               3816
_journal_paper_doi               10.1021/jacs.8b13827
_journal_volume                  141
_journal_year                    2019
_chemical_formula_sum            'C8 H24 Br7 Cs N2 Pb2'
_chemical_formula_weight         1254.95
_space_group_IT_number           64
_space_group_name_Hall           '-C 2ac 2'
_space_group_name_H-M_alt        'C m c e'
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_H-M   'C m c e'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   39.750(2)
_cell_length_b                   8.2718(4)
_cell_length_c                   8.2733(5)
_cell_measurement_reflns_used    2107
_cell_measurement_temperature    360(2)
_cell_measurement_theta_max      22.79
_cell_measurement_theta_min      3.07
_cell_volume                     2720.3(3)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      360(2)
_diffrn_measured_fraction_theta_full 0.997
_diffrn_measured_fraction_theta_max 0.997
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.1006
_diffrn_reflns_av_sigmaI/netI    0.0433
_diffrn_reflns_limit_h_max       49
_diffrn_reflns_limit_h_min       -49
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       -10
_diffrn_reflns_limit_l_max       10
_diffrn_reflns_limit_l_min       -10
_diffrn_reflns_number            15962
_diffrn_reflns_theta_full        26.38
_diffrn_reflns_theta_max         26.38
_diffrn_reflns_theta_min         3.07
_exptl_absorpt_coefficient_mu    23.957
_exptl_crystal_colour            yellow
_exptl_crystal_density_diffrn    3.064
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       sheet
_exptl_crystal_F_000             2200
_refine_diff_density_max         0.722
_refine_diff_density_min         -1.191
_refine_diff_density_rms         0.189
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.025
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     65
_refine_ls_number_reflns         1425
_refine_ls_number_restraints     40
_refine_ls_restrained_S_all      1.016
_refine_ls_R_factor_all          0.0855
_refine_ls_R_factor_gt           0.0453
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0489P)^2^+28.1719P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0995
_refine_ls_wR_factor_ref         0.1196
_reflns_number_gt                889
_reflns_number_total             1425
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ja8b13827_si_003.cif
_cod_data_source_block           c:\users\wu\desktop\12\a
_cod_original_sg_symbol_H-M      Cmca
_cod_database_code               4128537