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_2105069
_publ_section_title
;
 Structures and phase transitions in a new ferroelectric -- pyridinium
 chlorochromate -- studied by X-ray diffraction, DSC and dielectric
 methods
;
_journal_coeditor_code           EB5013
_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           166
_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                   9.021(2)
_cell_length_b                   9.021(2)
_cell_length_c                   9.369(4)
_cell_measurement_reflns_used    175
_cell_measurement_temperature    355.0(2)
_cell_measurement_theta_max      32.7751
_cell_measurement_theta_min      3.3750
_cell_volume                     660.3(3)
_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      355.0(2)
_diffrn_detector_area_resol_mean 10.3200
_diffrn_measured_fraction_theta_full 1.00
_diffrn_measured_fraction_theta_max 0.932
_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  0.0545
_diffrn_reflns_av_sigmaI/netI    0.0510
_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       8
_diffrn_reflns_limit_l_min       -13
_diffrn_reflns_number            1606
_diffrn_reflns_theta_full        30.00
_diffrn_reflns_theta_max         32.83
_diffrn_reflns_theta_min         3.40
_exptl_absorpt_coefficient_mu    1.561
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            orange
_exptl_crystal_density_diffrn    1.626
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prism
_exptl_crystal_F_000             324
_exptl_crystal_size_max          0.5
_exptl_crystal_size_mid          0.3
_exptl_crystal_size_min          0.3
_refine_diff_density_max         0.234
_refine_diff_density_min         -0.100
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.750
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     18
_refine_ls_number_reflns         305
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.750
_refine_ls_R_factor_all          0.3315
_refine_ls_R_factor_gt           0.0723
_refine_ls_shift/su_max          0.897
_refine_ls_shift/su_mean         0.317
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.1210P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1673
_refine_ls_wR_factor_ref         0.2681
_reflns_number_gt                44
_reflns_number_total             305
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            eb5013.cif
_cod_data_source_block           r-3m
_cod_original_cell_volume        660.2(4)
_cod_original_sg_symbol_H-M      R-3m
_cod_database_code               2105069
_cod_database_fobs_code          2105069