Alloying barbituric and thiobarbituric acids: from solid solutions to a highly stable keto co-crystal form.
Shemchuk, O.; Braga, D.; Grepioni, F.; Chemical communications (Cambridge, England) 52 (2016) 11815–11818; doi:10.1039/c6cc06615a

data_7125068
_publ_section_title
;
 Alloying barbituric and thiobarbituric acids: from solid solutions to a
 highly stable keto co-crystal form.
;
_journal_issue                   79
_journal_name_full
'Chemical communications (Cambridge, England)'
_journal_page_first              11815
_journal_page_last               11818
_journal_paper_doi               10.1039/c6cc06615a
_journal_volume                  52
_journal_year                    2016
_chemical_formula_sum            'C8 H8 N4 O5.4 S0.6'
_chemical_formula_weight         265.82
_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_sites_solution_hydrogens   geom
_audit_creation_method           SHELXL-2014/7
_audit_update_record
;
2016-08-10 deposited with the CCDC.
2016-09-02 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 92.626(10)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   8.4569(9)
_cell_length_b                   12.9400(10)
_cell_length_c                   9.5593(9)
_cell_measurement_reflns_used    737
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      22.9940
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_cell_volume                     1045.00(17)
_computing_cell_refinement
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CrysAlisPro, Agilent Technologies,
Version 1.171.37.35h (release 09-02-2015 CrysAlis171 .NET)
(compiled Feb  9 2015,16:26:32)
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_computing_data_collection
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CrysAlisPro, Agilent Technologies,
Version 1.171.37.35h (release 09-02-2015 CrysAlis171 .NET)
(compiled Feb  9 2015,16:26:32)
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_computing_data_reduction
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CrysAlisPro, Agilent Technologies,
Version 1.171.37.35h (release 09-02-2015 CrysAlis171 .NET)
(compiled Feb  9 2015,16:26:32)
;
_computing_structure_refinement  'SHELXL-2014/7 (Sheldrick, 2014)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 2005)'
_diffrn_ambient_temperature      295(2)
_diffrn_detector                 'CCD plate'
_diffrn_detector_area_resol_mean 16.1340
_diffrn_detector_type            Sapphire3
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.830
_diffrn_measurement_device       'four-circle diffractometer'
_diffrn_measurement_device_type  'Xcalibur, Sapphire3'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0704
_diffrn_reflns_av_unetI/netI     0.1280
_diffrn_reflns_Laue_measured_fraction_full 0.998
_diffrn_reflns_Laue_measured_fraction_max 0.830
_diffrn_reflns_limit_h_max       11
_diffrn_reflns_limit_h_min       -10
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       -17
_diffrn_reflns_limit_l_max       13
_diffrn_reflns_limit_l_min       -6
_diffrn_reflns_number            4818
_diffrn_reflns_point_group_measured_fraction_full 0.998
_diffrn_reflns_point_group_measured_fraction_max 0.830
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         29.473
_diffrn_reflns_theta_min         3.518
_diffrn_source                   'Enhance (Mo) X-ray Source'
_exptl_absorpt_coefficient_mu    0.256
_exptl_absorpt_correction_T_max  1.00000
_exptl_absorpt_correction_T_min  0.95550
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
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CrysAlisPro, Agilent Technologies,
Version 1.171.37.35h (release 09-02-2015 CrysAlis171 .NET)
(compiled Feb  9 2015,16:26:32)
Empirical absorption correction using spherical harmonics,
 implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.690
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prism
_exptl_crystal_F_000             547
_exptl_crystal_size_max          0.13
_exptl_crystal_size_mid          0.10
_exptl_crystal_size_min          0.08
_refine_diff_density_max         0.275
_refine_diff_density_min         -0.273
_refine_diff_density_rms         0.061
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.985
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     181
_refine_ls_number_reflns         2417
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.985
_refine_ls_R_factor_all          0.2080
_refine_ls_R_factor_gt           0.0743
_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^)+(0.0399P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1139
_refine_ls_wR_factor_ref         0.1604
_reflns_number_gt                956
_reflns_number_total             2417
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            c6cc06615a2.cif
_cod_data_source_block           shelx
_cod_original_sg_symbol_H-M      'P 21/c'
_cod_original_formula_sum        'C8 H8 N4 O5.40 S0.60'
_cod_database_code               7125068
_shelx_shelxl_version_number     2014/7
_shelx_res_checksum              40496
_shelx_hkl_checksum              8223