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_7125067
_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            'C4 H4 N2 O2.5 S0.5'
_chemical_formula_weight         136.12
_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                 92.1310(10)
_cell_angle_gamma                90
_cell_formula_units_Z            8
_cell_length_a                   8.5330(10)
_cell_length_b                   13.0141(10)
_cell_length_c                   9.6918(12)
_cell_measurement_reflns_used    820
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      28.4520
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_cell_volume                     1075.5(2)
_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 0.997
_diffrn_measured_fraction_theta_max 0.829
_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  0.0464
_diffrn_reflns_av_unetI/netI     0.0959
_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       -8
_diffrn_reflns_limit_k_max       17
_diffrn_reflns_limit_k_min       -15
_diffrn_reflns_limit_l_max       9
_diffrn_reflns_limit_l_min       -13
_diffrn_reflns_number            4693
_diffrn_reflns_point_group_measured_fraction_full 0.997
_diffrn_reflns_point_group_measured_fraction_max 0.829
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         29.356
_diffrn_reflns_theta_min         2.856
_diffrn_source                   'Enhance (Mo) X-ray Source'
_exptl_absorpt_coefficient_mu    0.324
_exptl_absorpt_correction_type   multi-scan
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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.
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_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.681
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prism
_exptl_crystal_F_000             560
_exptl_crystal_size_max          0.12
_exptl_crystal_size_mid          0.09
_exptl_crystal_size_min          0.08
_exptl_transmission_factor_max   1.00000
_exptl_transmission_factor_min   0.84176
_refine_diff_density_max         0.245
_refine_diff_density_min         -0.234
_refine_diff_density_rms         0.057
_refine_ls_extinction_coef       0.0020(7)
_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   1.167
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     182
_refine_ls_number_reflns         2458
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.167
_refine_ls_R_factor_all          0.1644
_refine_ls_R_factor_gt           0.0856
_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^)+(0.0349P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1302
_refine_ls_wR_factor_ref         0.1552
_reflns_number_gt                1359
_reflns_number_total             2458
_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        'C4 H4 N2 O2.50 S0.50'
_cod_database_code               7125067
_shelx_shelxl_version_number     2014/7
_exptl_absorpt_special_details
;
 ?   
;
_shelx_res_checksum              81622
_shelx_hkl_checksum              66055