Ambiguous structure determination from powder data: four different structural models of 4,11-difluoroquinacridone with similar X-ray powder patterns, fit to the PDF, SSNMR and DFT-D
Schlesinger, Carina; Fitterer, Arnd; Buchsbaum, Christian; Habermehl, Stefan; Chierotti, Michele R.; Nervi, Carlo; Schmidt, Martin U.; IUCrJ 9 (2022) –; doi:10.1107/S2052252522004237

data_1566975
_publ_section_title
;
 Ambiguous structure determination from powder data: four different
 structural models of 4,11-difluoroquinacridone with similar X-ray powder
 patterns, fit to the PDF, SSNMR and DFT-D
;
_journal_coeditor_code           LT5047SUP1
_journal_issue                   4
_journal_name_full               IUCrJ
_journal_paper_doi               10.1107/S2052252522004237
_journal_volume                  9
_journal_year                    2022
_chemical_formula_moiety         'C20 H10 F2 N2 O2'
_chemical_formula_sum            'C20 H10 F2 N2 O2'
_chemical_formula_weight         348.3016
_chemical_name_common
;
4,11-Difluoro-quinacridone
(Structural model B)
Structure refined by fit to the pair-distribution function
;
_chemical_name_systematic
4,11-Difluoroquino[2,3-b]acridine-7,14(5H,12H)-dione
_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_site_refinement_flags_posn R
_cell_angle_alpha                90
_cell_angle_beta                 103.09(15)
_cell_angle_gamma                90
_cell_formula_units_Z            2
_cell_length_a                   14.166(17)
_cell_length_b                   3.758(3)
_cell_length_c                   13.762(14)
_cell_measurement_temperature    298
_cell_measurement_theta_max      53.4
_cell_measurement_theta_min      0
_cell_volume                     713.6(13)
_computing_cell_refinement       '<i>TOPAS-Academic</i> (Coelho, 2019)'
_computing_data_reduction        '<i>PDFgetX3<i> (Juhas,2012)'
_computing_molecular_graphics    '<i>Mercury</i> (Macrae <i>et al.</i>, 2008)'
_computing_structure_refinement  '<i>TOPAS-Academic</i> (Coelho, 2019)'
_diffrn_ambient_temperature      298
_diffrn_measurement_device_type
'I15-1, Diamond Light Source, Didcot, United Kingdom'
_diffrn_radiation_monochromator  'Bent Laue-monochromator'
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           Synchrotron
_diffrn_radiation_wavelength     0.1631
_exptl_absorpt_coefficient_mu    0.028
_exptl_crystal_density_diffrn    1.621
_exptl_crystal_description       powder
_exptl_crystal_F_000             356
_pd_calc_method                  'Fit to the pair distribution function'
_pd_char_colour                  orange
_pd_char_particle_morphology     powder
_pd_instr_beam_size_ax           700
_pd_instr_beam_size_eq           150
_pd_meas_2theta_range_max        53.4
_pd_meas_2theta_range_min        0.0
_pd_meas_counts_container        capillary
_pd_proc_2theta_range_max        53.4
_pd_proc_2theta_range_min        0
_pd_proc_ls_background_function
'background measurement of an empty capillary, substracted with an factor of 0.962257'
_pd_proc_ls_prof_wR_factor       0.2807
_pd_spec_mounting                '1 mm glass capillary'
_pd_spec_mount_mode              transmission
_pd_spec_shape                   powder
_refine_ls_extinction_method     none
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           fullcycle
_refine_ls_shift/su_max          0.001
_cod_data_source_file            lt5047.cif
_cod_data_source_block           DFQ_model_B_PDF-fit
_cod_depositor_comments
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The following automatic conversions were performed:

data item '_diffrn_radiation_probe' value 'X-ray' was changed to
'x-ray' in accordance with the
/home/data/users/saulius/crontab/automatic-downloads/rss-feeds/IUCr/lib/dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.2 last updated on
2011-04-26.

Automatic conversion script
Id: cif_fix_values 7556 2019-12-06 15:28:31Z antanas 
;
_cod_original_cell_volume        713.5(13)
_cod_original_sg_symbol_H-M      'P 21/c'
_cod_database_code               1566975