Tetragonal polymorph of 5,5-dichlorobarbituric acid
Gelbrich, Thomas; Rossi, Denise; Griesser, Ulrich J.; Acta Crystallographica Section E 68 (2012) o235–o236; doi:10.1107/S1600536811054626

data_2233298
_publ_section_title
;
 Tetragonal polymorph of 5,5-dichlorobarbituric acid
;
_journal_coeditor_code           SU2351
_journal_issue                   1
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              o235
_journal_page_last               o236
_journal_paper_doi               10.1107/S1600536811054626
_journal_volume                  68
_journal_year                    2012
_chemical_formula_iupac          'C4 H2 Cl2 N2 O3'
_chemical_formula_moiety         'C4 H2 Cl2 N2 O3'
_chemical_formula_sum            'C4 H2 Cl2 N2 O3'
_chemical_formula_weight         196.98
_chemical_melting_point          478
_chemical_name_common            '5,5-dichlorobarbituric acid'
_chemical_name_systematic
;
5,5-dichlorobarbituric acid
;
_space_group_IT_number           114
_symmetry_cell_setting           tetragonal
_symmetry_space_group_name_Hall  'P -4 2n'
_symmetry_space_group_name_H-M   'P -4 21 c'
_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                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   13.8883(3)
_cell_length_b                   13.8883(3)
_cell_length_c                   6.9126(2)
_cell_measurement_reflns_used    5173
_cell_measurement_temperature    173(2)
_cell_measurement_theta_max      29.3300
_cell_measurement_theta_min      2.9275
_cell_volume                     1333.34(6)
_computing_cell_refinement
;
CrysAlis PRO (Oxford Diffraction, 2003)
;
_computing_data_collection
;
CrysAlis PRO (Oxford Diffraction, 2003)
;
_computing_data_reduction
;
CrysAlis RED (Oxford Diffraction, 2003)
;
_computing_molecular_graphics
'SHELXTL (Sheldrick, 2008) and Mercury (Macrae <i>et al.</i>, 2008)'
_computing_publication_material  'publCIF (Westrip, 2010)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      173(2)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'Oxford Diffraction Xcalibur Ruby Gemini ultra'
_diffrn_measurement_method       '\w scans'
_diffrn_radiation_monochromator  mirror
_diffrn_radiation_source         'Enhance Ultra (Mo) X-ray Source'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0408
_diffrn_reflns_av_sigmaI/netI    0.0214
_diffrn_reflns_limit_h_max       17
_diffrn_reflns_limit_h_min       -17
_diffrn_reflns_limit_k_max       17
_diffrn_reflns_limit_k_min       -16
_diffrn_reflns_limit_l_max       8
_diffrn_reflns_limit_l_min       -7
_diffrn_reflns_number            11025
_diffrn_reflns_theta_full        25.00
_diffrn_reflns_theta_max         25.99
_diffrn_reflns_theta_min         2.93
_diffrn_standards_decay_%        0
_diffrn_standards_interval_count 0
_diffrn_standards_interval_time  0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.924
_exptl_absorpt_correction_T_max  0.9553
_exptl_absorpt_correction_T_min  0.8368
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
(CrysAlis RED; Oxford Diffraction, 2003)
;
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.963
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             784
_exptl_crystal_size_max          0.20
_exptl_crystal_size_mid          0.05
_exptl_crystal_size_min          0.05
_refine_diff_density_max         0.201
_refine_diff_density_min         -0.158
_refine_ls_abs_structure_details 'Flack (1983), <b>541 Friedel pairs</b>'
_refine_ls_abs_structure_Flack   -0.08(7)
_refine_ls_extinction_coef       0.0046(8)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     'SHELXL97 (Sheldrick, 2008)'
_refine_ls_goodness_of_fit_ref   1.072
_refine_ls_hydrogen_treatment    refall
_refine_ls_matrix_type           full
_refine_ls_number_parameters     107
_refine_ls_number_reflns         1310
_refine_ls_number_restraints     2
_refine_ls_restrained_S_all      1.075
_refine_ls_R_factor_all          0.0216
_refine_ls_R_factor_gt           0.0198
_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^)+(0.0266P)^2^+0.2183P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0488
_refine_ls_wR_factor_ref         0.0495
_reflns_number_gt                1242
_reflns_number_total             1310
_reflns_threshold_expression     I>2sigma(I)
_cod_data_source_file            su2351.cif
_cod_data_source_block           I
_cod_database_code               2233298
_cod_database_fobs_code          2233298