High-pressure polymorphism in pyridine
Giordano, Nico; Beavers, Christine M.; Campbell, Branton J.; Eigner, Václav; Gregoryanz, Eugene; Marshall, Willliam G.; Peña-Álvarez, Miriam; Teat, Simon J.; Vennari, Cara E.; Parsons, Simon; IUCrJ 7 (2020) 58–70; doi:10.1107/S2052252519015616

data_1556894
_publ_section_title
;
 High-pressure polymorphism in pyridine
;
_journal_issue                   1
_journal_name_full               IUCrJ
_journal_page_first              58
_journal_page_last               70
_journal_paper_doi               10.1107/S2052252519015616
_journal_volume                  7
_journal_year                    2020
_chemical_formula_moiety         'C5 H5 N'
_chemical_formula_sum            'C5 H5 N'
_chemical_formula_weight         79.10
_chemical_name_systematic        'Pyridine III'
_space_group_crystal_system      tetragonal
_space_group_IT_number           92
_space_group_name_Hall           'P 4abw 2nw'
_space_group_name_H-M_alt        'P 41 21 2'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     dual
_audit_creation_date             2017-11-13
_audit_creation_method
;
Olex2 1.2
(compiled 2017.08.10 svn.r3458 for OlexSys, GUI svn.r5381)
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   5.4053(4)
_cell_length_b                   5.4053(4)
_cell_length_c                   13.4853(14)
_cell_measurement_reflns_used    1185
_cell_measurement_temperature    293
_cell_measurement_theta_max      19.512
_cell_measurement_theta_min      2.833
_cell_volume                     394.00(6)
_computing_cell_refinement       'SAINT V8.38A Bruker-AXS, Madison WI'
_computing_data_collection       'SAINT V8.38A Bruker-AXS, Madison WI'
_computing_data_reduction        'SAINT V8.38A Bruker-AXS, Madison WI'
_computing_molecular_graphics    'Olex2 (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 (Dolomanov et al., 2009)'
_computing_structure_refinement  'XL (Sheldrick, 2008)'
_computing_structure_solution    'XT (Sheldrick, 2015)'
_diffrn_ambient_temperature      293
_diffrn_detector_area_resol_mean 10.42
_diffrn_measured_fraction_theta_full 0.772
_diffrn_measured_fraction_theta_max 0.762
_diffrn_measurement_device_type  'Perkin-Elmer a-Si Detector'
_diffrn_measurement_method       '\f shutterless scans'
_diffrn_radiation_monochromator  'silicon 111'
_diffrn_radiation_type           synchrotron
_diffrn_radiation_wavelength     0.49594
_diffrn_reflns_av_R_equivalents  0.0613
_diffrn_reflns_av_unetI/netI     0.0459
_diffrn_reflns_Laue_measured_fraction_full 0.772
_diffrn_reflns_Laue_measured_fraction_max 0.762
_diffrn_reflns_limit_h_max       6
_diffrn_reflns_limit_h_min       -6
_diffrn_reflns_limit_k_max       6
_diffrn_reflns_limit_k_min       -6
_diffrn_reflns_limit_l_max       13
_diffrn_reflns_limit_l_min       -13
_diffrn_reflns_number            1328
_diffrn_reflns_point_group_measured_fraction_full 0.805
_diffrn_reflns_point_group_measured_fraction_max 0.797
_diffrn_reflns_theta_full        17.311
_diffrn_reflns_theta_max         18.055
_diffrn_reflns_theta_min         2.833
_diffrn_source
;
Advanced Light Source, station 12.2.2
;
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.044
_exptl_absorpt_correction_T_max  0.7447
_exptl_absorpt_correction_T_min  0.5853
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
SADABS-2016/2 (Bruker,2016/2) was used for absorption correction. 
wR2(int) was 0.1460 before and 0.0858 after correction. The Ratio of 
minimum to maximum transmission is 0.7860. The \l/2 correction factor is 
not present.
;
_exptl_crystal_colour            colourless
_exptl_crystal_colour_primary    colourless
_exptl_crystal_density_diffrn    1.333
_exptl_crystal_description       irregular
_exptl_crystal_F_000             168
_exptl_crystal_recrystallization_method
;
Grown in-situ at 1.55 GPa. Heated to ca. 130 C and cooled to room temp. 
This process was cycled until only a few large cyrstals remained. 
No hydrostatic medium was used.
;
_exptl_crystal_size_max          0.35
_exptl_crystal_size_mid          0.35
_exptl_crystal_size_min          0.1
_refine_diff_density_max         0.248
_refine_diff_density_min         -0.305
_refine_diff_density_rms         0.081
_refine_ls_abs_structure_details
;
 Flack x determined using 87 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   -10.0(10)
_refine_ls_extinction_coef       7.3(16)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     'SHELXL-2014/7 (Sheldrick 2014'
_refine_ls_goodness_of_fit_ref   1.137
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     30
_refine_ls_number_reflns         326
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.137
_refine_ls_R_factor_all          0.0786
_refine_ls_R_factor_gt           0.0755
_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^)+(0.1400P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1864
_refine_ls_wR_factor_ref         0.1956
_reflns_Friedel_coverage         0.516
_reflns_Friedel_fraction_full    0.883
_reflns_Friedel_fraction_max     0.874
_reflns_number_gt                297
_reflns_number_total             326
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            lq5025.cif
_cod_data_source_block           pyridine3_final
_cod_original_cell_volume        394.00(7)
_cod_database_code               1556894
_shelx_shelxl_version_number     2014/7
_shelx_estimated_absorpt_t_max   0.996
_shelx_estimated_absorpt_t_min   0.985
_olex2_refinement_description
;
1. Fixed Uiso
 At 1.2 times of:
  All C(H) groups
2.a Aromatic/amide H refined with riding coordinates:
 C2(H2), C3(H3), C4(H4)
;
_shelx_res_checksum              57503
_shelx_hkl_checksum              18407
_olex2_submission_original_sample_id 'Pyridine III'
_olex2_submission_special_instructions 'No special instructions were received'