Reversible structural phase transition of pyridinium-4-carboxylic acid perchlorate
Ye, Heng-Yun; Cai, Hong-Ling; Ge, Jia-Zeng; Xiong, Ren-Gen; Journal of Applied Crystallography 43 (2010) 1031–1035; doi:10.1107/S0021889810024039

data_2300301
_publ_section_title
;
 Reversible structural phase transition of pyridinium-4-carboxylic acid
 perchlorate
;
_journal_coden_ASTM              JACGAR
_journal_issue                   5
_journal_name_full               'Journal of Applied Crystallography'
_journal_page_first              1031
_journal_page_last               1035
_journal_paper_doi               10.1107/S0021889810024039
_journal_volume                  43
_journal_year                    2010
_chemical_formula_sum            'C6 H6 Cl N O6'
_chemical_formula_weight         223.57
_chemical_name_systematic
;
 ?
;
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/c 1'
_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                 137.919(17)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   5.5046(11)
_cell_length_b                   13.574(3)
_cell_length_c                   17.423(5)
_cell_measurement_temperature    298(2)
_cell_volume                     872.5(5)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      298(2)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_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  0.0388
_diffrn_reflns_av_sigmaI/netI    0.0323
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_k_max       17
_diffrn_reflns_limit_k_min       -17
_diffrn_reflns_limit_l_max       22
_diffrn_reflns_limit_l_min       -22
_diffrn_reflns_number            8786
_diffrn_reflns_theta_full        27.48
_diffrn_reflns_theta_max         27.48
_diffrn_reflns_theta_min         3.00
_exptl_absorpt_coefficient_mu    0.443
_exptl_absorpt_correction_T_max  1.0000
_exptl_absorpt_correction_T_min  0.8771
_exptl_absorpt_correction_type   multi-scan
_exptl_crystal_density_diffrn    1.702
_exptl_crystal_density_method    'not measured'
_exptl_crystal_F_000             456
_exptl_crystal_size_max          0.42
_exptl_crystal_size_mid          0.30
_exptl_crystal_size_min          0.30
_refine_diff_density_max         0.734
_refine_diff_density_min         -0.425
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.072
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     158
_refine_ls_number_reflns         1998
_refine_ls_number_restraints     79
_refine_ls_restrained_S_all      1.070
_refine_ls_R_factor_all          0.0805
_refine_ls_R_factor_gt           0.0585
_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^)+(0.0796P)^2^+0.7580P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1551
_refine_ls_wR_factor_ref         0.1699
_reflns_number_gt                1484
_reflns_number_total             1998
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            wf5065.cif
_cod_data_source_block           298K
_cod_original_cell_volume        872.5(3)
_cod_original_sg_symbol_H-M      'p 21/c'
_cod_database_code               2300301