Structures and phase transitions in a new ferroelectric ‒ pyridinium chlorochromate ‒ studied by X-ray diffraction, DSC and dielectric methods
Małuszyńska, Hanna; Czarnecki, Piotr; Czarnecka, Anna; Pajak, Zdzisław; Acta Crystallographica Section B 68 (2012) 128–136; doi:10.1107/S0108768112005782

data_2105070
_publ_section_title
;
 Structures and phase transitions in a new ferroelectric -- pyridinium
 chlorochromate -- studied by X-ray diffraction, DSC and dielectric
 methods
;
_journal_issue                   2
_journal_name_full               'Acta Crystallographica Section B'
_journal_page_first              128
_journal_page_last               136
_journal_paper_doi               10.1107/S0108768112005782
_journal_volume                  68
_journal_year                    2012
_chemical_formula_moiety         '[C5H5 NH]+ [Cl Cr O3]- '
_chemical_formula_sum            'C5 H6 Cl Cr N O3'
_chemical_formula_weight         215.56
_chemical_name_systematic
;
 pyridinium chlorochromate
;
_space_group_IT_number           160
_symmetry_cell_setting           trigonal
_symmetry_space_group_name_Hall  'R 3 -2"'
_symmetry_space_group_name_H-M   'R 3 m :H'
_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                120.00
_cell_formula_units_Z            3
_cell_length_a                   8.8349(12)
_cell_length_b                   8.8349(12)
_cell_length_c                   9.3960(16)
_cell_measurement_reflns_used    835
_cell_measurement_temperature    320.0(2)
_cell_measurement_theta_max      28.9376
_cell_measurement_theta_min      3.4270
_cell_volume                     635.15(16)
_computing_cell_refinement       'CrysAlis CCD (Oxford Diffraction,2009)'
_computing_data_collection       'CrysAlis CCD (Oxford Diffraction,2009)'
_computing_data_reduction        'CrysAlis RED (Oxford Diffraction,2009)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      320.0(2)
_diffrn_detector_area_resol_mean 10.3200
_diffrn_measured_fraction_theta_full 0.952
_diffrn_measured_fraction_theta_max 0.952
_diffrn_measurement_device_type  'Xcalibur, Atlas, Gemini ultra'
_diffrn_measurement_method       'omega scan'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'Enhance (Mo) X-ray Source'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0330
_diffrn_reflns_av_sigmaI/netI    0.0348
_diffrn_reflns_limit_h_max       12
_diffrn_reflns_limit_h_min       -8
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       -11
_diffrn_reflns_limit_l_max       11
_diffrn_reflns_limit_l_min       -11
_diffrn_reflns_number            1845
_diffrn_reflns_theta_full        28.93
_diffrn_reflns_theta_max         28.93
_diffrn_reflns_theta_min         3.43
_exptl_absorpt_coefficient_mu    1.623
_exptl_absorpt_correction_T_max  1.0000
_exptl_absorpt_correction_T_min  0.66703
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
 CrysAlisPro, Oxford Diffraction Ltd.,
Version 1.171.33.64 (release 22-03-2010 CrysAlis171 .NET)
(compiled Mar 22 2010,13:57:49)
Empirical absorption correction using spherical harmonics,
 implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            orange
_exptl_crystal_density_diffrn    1.691
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prism
_exptl_crystal_F_000             324
_exptl_crystal_size_max          0.70
_exptl_crystal_size_mid          0.25
_exptl_crystal_size_min          0.15
_refine_diff_density_max         0.912
_refine_diff_density_min         -0.245
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.01(7)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.977
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     22
_refine_ls_number_reflns         401
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      0.975
_refine_ls_R_factor_all          0.1015
_refine_ls_R_factor_gt           0.0493
_refine_ls_shift/su_max          0.016
_refine_ls_shift/su_mean         0.004
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0992P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1056
_refine_ls_wR_factor_ref         0.1148
_reflns_number_gt                194
_reflns_number_total             401
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            eb5013.cif
_cod_data_source_block           r3m
_cod_original_sg_symbol_H-M      R3m
_cod_database_code               2105070
_cod_database_fobs_code          2105070