Indications of ferroelectric behaviour near room temperature in the organic-inorganic hybrid Q<sub>2</sub>CuBr<sub>4</sub>.
Ciżman, Agnieszka; Kowalska, Dorota A.; Szarek, Paweł; Medycki, Wojciech; Wójcik, Natalia A; Gusowski, Marek; Trzebiatowska, Monika; Bartosiewicz, Adam; Filevska, Liudmyla; Staniorowski, Piotr; Jach, Ewelina; Dalton transactions (Cambridge, England : 2003) 54 (2025) 15816–15832; doi:10.1039/d5dt01668a

data_7719531
_publ_section_title
;
 Indications of ferroelectric behaviour near room temperature in the
 organic-inorganic hybrid Q<sub>2</sub>CuBr<sub>4</sub>.
;
_journal_issue                   42
_journal_name_full
'Dalton transactions (Cambridge, England : 2003)'
_journal_page_first              15816
_journal_page_last               15832
_journal_paper_doi               10.1039/d5dt01668a
_journal_volume                  54
_journal_year                    2025
_chemical_formula_moiety         'Br4 Cu, 2(C7 H14 N)'
_chemical_formula_sum            'C14 H28 Br4 Cu N2'
_chemical_formula_weight         607.56
_space_group_crystal_system      monoclinic
_space_group_IT_number           14
_space_group_name_Hall           '-P 2ybc'
_space_group_name_H-M_alt        'P 1 21/c 1'
_atom_sites_solution_hydrogens   mixed
_audit_creation_date             2025-01-15
_audit_creation_method
;
Olex2 1.5
(compiled 2022.04.07 svn.rca3783a0 for OlexSys, GUI svn.r6498)
;
_audit_update_record
;
2025-01-15 deposited with the CCDC.	2025-09-26 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 93.34(3)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   9.552(3)
_cell_length_b                   17.154(5)
_cell_length_c                   12.593(4)
_cell_measurement_reflns_used    4000
_cell_measurement_temperature    300.01(10)
_cell_measurement_theta_max      25.8450
_cell_measurement_theta_min      3.4280
_cell_volume                     2059.9(11)
_computing_cell_refinement       'CrysAlisPro 1.171.39.46 (Rigaku OD, 2018)'
_computing_data_collection       'CrysAlisPro 1.171.39.46 (Rigaku OD, 2018)'
_computing_data_reduction        'CrysAlisPro 1.171.39.46 (Rigaku OD, 2018)'
_computing_molecular_graphics    'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_structure_refinement  'SHELXL 2018/3 (Sheldrick, 2015)'
_diffrn_ambient_temperature      300.01(10)
_diffrn_detector_area_resol_mean 10.6249
_diffrn_detector_type            Atlas
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.939
_diffrn_measurement_details
;
List of Runs (angles in degrees, time in seconds):

  # Type    Start    End  Width  t~exp~   \w     \q     \k     \f   Frames
  1  \w    -23.00  97.00   0.60   12.50    --   13.31  77.00 -30.00  200
  2  \w    -50.00  70.00   0.60   12.50    --  -14.40  77.00-180.00  200
  3  \w    -25.00  28.40   0.60   12.50    --   13.31 -99.00  30.00   89
;
_diffrn_measurement_device       'four-circle diffractometer'
_diffrn_measurement_device_type  'Xcalibur, Atlas'
_diffrn_measurement_method       '\w scans'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0269
_diffrn_reflns_av_unetI/netI     0.0377
_diffrn_reflns_Laue_measured_fraction_full 0.999
_diffrn_reflns_Laue_measured_fraction_max 0.939
_diffrn_reflns_limit_h_max       12
_diffrn_reflns_limit_h_min       -12
_diffrn_reflns_limit_k_max       21
_diffrn_reflns_limit_k_min       -22
_diffrn_reflns_limit_l_max       16
_diffrn_reflns_limit_l_min       -16
_diffrn_reflns_number            14987
_diffrn_reflns_point_group_measured_fraction_full 0.999
_diffrn_reflns_point_group_measured_fraction_max 0.939
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         28.318
_diffrn_reflns_theta_min         2.444
_exptl_absorpt_coefficient_mu    8.815
_exptl_absorpt_correction_T_max  0.328
_exptl_absorpt_correction_T_min  0.170
_exptl_absorpt_correction_type   gaussian
_exptl_absorpt_process_details
;
CrysAlisPro 1.171.39.46 (Rigaku Oxford Diffraction, 2018)
Numerical absorption correction based on gaussian integration over
			a multifaceted crystal model
Empirical absorption correction using spherical harmonics,
 implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            black
_exptl_crystal_colour_primary    black
_exptl_crystal_density_diffrn    1.959
_exptl_crystal_description       block
_exptl_crystal_F_000             1180
_exptl_crystal_size_max          0.293
_exptl_crystal_size_mid          0.233
_exptl_crystal_size_min          0.169
_refine_diff_density_max         0.934
_refine_diff_density_min         -0.692
_refine_diff_density_rms         0.095
_refine_ls_extinction_coef       0.0024(2)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     'SHELXL-2018/3 (Sheldrick 2018)'
_refine_ls_goodness_of_fit_ref   1.018
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     191
_refine_ls_number_reflns         4829
_refine_ls_number_restraints     2
_refine_ls_restrained_S_all      1.018
_refine_ls_R_factor_all          0.0875
_refine_ls_R_factor_gt           0.0474
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0293P)^2^+6.8273P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0917
_refine_ls_wR_factor_ref         0.1077
_reflns_Friedel_coverage         0.000
_reflns_number_gt                3118
_reflns_number_total             4829
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d5dt01668a2.cif
_cod_data_source_block           QCuBr_300K
_cod_depositor_comments
'Adding full bibliography for 7719531--7719532.cif.'
_cod_database_code               7719531
_shelx_shelxl_version_number     2018/3
_olex2_refinement_description
;
1. Fixed Uiso
 At 1.2 times of:
  All C(H) groups, All C(H,H) groups, All N(H) groups
2. Restrained distances
 N2-H2
 0.98 with sigma of 0.02
 C14-H14
 0.98 with sigma of 0.02
3. Others
 Fixed Sof: C8(0.5) H8A(0.5) H8B(0.5) C9(0.5) H9A(0.5) H9B(0.5) C10(0.5)
 H10A(0.5) H10B(0.5) C11(0.5) H11A(0.5) H11B(0.5) C12(0.5) H12A(0.5) H12B(0.5)
 C13(0.5) H13A(0.5) H13B(0.5) C15(0.5) H15A(0.5) H15B(0.5) C16(0.5) H16A(0.5)
 H16B(0.5) C17(0.5) H17A(0.5) H17B(0.5) C18(0.5) H18A(0.5) H18B(0.5) C19(0.5)
 H19A(0.5) H19B(0.5) C20(0.5) H20A(0.5) H20B(0.5)
4.a Ternary CH refined with riding coordinates:
 N1(H1), C7(H7)
4.b Secondary CH2 refined with riding coordinates:
 C1(H1A,H1B), C2(H2A,H2B), C3(H3A,H3B), C4(H4A,H4B), C5(H5A,H5B), C6(H6A,H6B),
 C8(H8A,H8B), C9(H9A,H9B), C10(H10A,H10B), C11(H11A,H11B), C12(H12A,H12B),
 C13(H13A,H13B), C15(H15A,H15B), C16(H16A,H16B), C17(H17A,H17B), C18(H18A,H18B),
  C19(H19A,H19B), C20(H20A,H20B)
;
_shelx_res_checksum              60700
_olex2_submission_special_instructions 'No special instructions were received'
_oxdiff_exptl_absorpt_empirical_details
;
Empirical correction (ABSPACK) includes:
- Absorption correction using spherical harmonics
- Frame scaling
;