Two-dimensional Lead-Free Double Perovskite Ferroelastic with Dynamic Thermochromism
Su, Chang-Yuan; Yi, Heng-Guan; Ni, Hao-Fei; Du, Guowei; Xia, San-Qiang; Liu, Zunqi; Zhang, Zhi-Xu; Fu, Da-Wei; Chemical Science  (2025) –; doi:10.1039/D5SC05158D

data_1576183
_publ_section_title
;
 Two-dimensional Lead-Free Double Perovskite Ferroelastic with Dynamic
 Thermochromism
;
_journal_name_full               'Chemical Science'
_journal_paper_doi               10.1039/D5SC05158D
_journal_year                    2025
_chemical_formula_moiety         'Br4 Pb, 2(C5 H12 N)'
_chemical_formula_sum            'C10 H24 Br4 N2 Pb'
_chemical_formula_weight         699.14
_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   geom
_audit_creation_date             2023-07-19
_audit_creation_method
;
Olex2 1.5
(compiled 2022.04.07 svn.rca3783a0 for OlexSys, GUI svn.r6498)
;
_audit_update_record
;
2023-09-04 deposited with the CCDC.	2025-10-27 downloaded from the CCDC.
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_cell_angle_alpha                90
_cell_angle_beta                 99.762(12)
_cell_angle_gamma                90
_cell_formula_units_Z            2
_cell_length_a                   14.339(7)
_cell_length_b                   8.289(3)
_cell_length_c                   8.232(3)
_cell_measurement_reflns_used    2945
_cell_measurement_temperature    283.00
_cell_measurement_theta_max      22.80
_cell_measurement_theta_min      2.88
_cell_volume                     964.3(7)
_computing_cell_refinement       'SAINT V8.40B (?, 2016)'
_computing_data_reduction        'SAINT V8.40B (?, 2016)'
_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)'
_computing_structure_solution    'SHELXT 2018/2 (Sheldrick, 2018)'
_diffrn_ambient_temperature      283.00
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.997
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.1442
_diffrn_reflns_av_unetI/netI     0.0626
_diffrn_reflns_Laue_measured_fraction_full 0.998
_diffrn_reflns_Laue_measured_fraction_max 0.997
_diffrn_reflns_limit_h_max       17
_diffrn_reflns_limit_h_min       -17
_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            23660
_diffrn_reflns_point_group_measured_fraction_full 0.998
_diffrn_reflns_point_group_measured_fraction_max 0.997
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         26.414
_diffrn_reflns_theta_min         2.849
_diffrn_source_current           1.4
_diffrn_source_power             0.07
_diffrn_source_voltage           50.0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    17.021
_exptl_absorpt_correction_T_max  0.7454
_exptl_absorpt_correction_T_min  0.3998
_exptl_absorpt_correction_type   none
_exptl_absorpt_process_details
;
SADABS-2016/2 (Bruker,2016/2) was used for absorption correction.
wR2(int) was 0.1444 before and 0.0892 after correction.
The Ratio of minimum to maximum transmission is 0.5364.
The \l/2 correction factor is Not present.
;
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    2.408
_exptl_crystal_description       block
_exptl_crystal_F_000             640
_refine_diff_density_max         2.838
_refine_diff_density_min         -2.075
_refine_diff_density_rms         0.223
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.017
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     80
_refine_ls_number_reflns         1978
_refine_ls_number_restraints     27
_refine_ls_restrained_S_all      1.022
_refine_ls_R_factor_all          0.0662
_refine_ls_R_factor_gt           0.0447
_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^)+(0.0657P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1076
_refine_ls_wR_factor_ref         0.1196
_reflns_Friedel_coverage         0.000
_reflns_number_gt                1477
_reflns_number_total             1978
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d5sc05158d4.cif
_cod_data_source_block           mo_scy_pbbr_cba_0m_a
_cod_database_code               1576183
_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,H,H) groups
2. Restrained distances
 C8-C10 = C8-C1
 1.5 with sigma of 0.02
 C7-C10
 1.5 with sigma of 0.02
3. Uiso/Uaniso restraints and constraints
C1 \\sim C8 \\sim C10 \\sim C7: within 2A with sigma of 0.04 and sigma for
terminal atoms of 0.08 within 2A
4.a Ternary CH refined with riding coordinates:
 C8(H8)
4.b Secondary CH2 refined with riding coordinates:
 C5(H5A,H5B), C10(H10A,H10B), C1(H1A,H1B), C7(H7A,H7B)
4.c Idealised Me refined as rotating group:
 N004(H00A,H00B,H00C)
;
_shelx_res_checksum              40436
_olex2_submission_special_instructions 'No special instructions were received'