5,6-Dimethylpyrazine-2,3-dicarboxylic acid
Liu, Fu-Hong; Acta Crystallographica Section E 68 (2012) o132–; doi:10.1107/S1600536811052366

data_2233219
_publ_section_title
;
 5,6-Dimethylpyrazine-2,3-dicarboxylic acid
;
_journal_coeditor_code           JJ2111
_journal_issue                   1
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              o132
_journal_paper_doi               10.1107/S1600536811052366
_journal_volume                  68
_journal_year                    2012
_chemical_formula_iupac          'C8 H8 N2 O4'
_chemical_formula_moiety         'C8 H8 N2 O4'
_chemical_formula_sum            'C8 H8 N2 O4'
_chemical_formula_weight         196.16
_chemical_name_systematic
;
5,6-Dimethylpyrazine-2,3-dicarboxylic acid
;
_space_group_IT_number           15
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-C 2yc'
_symmetry_space_group_name_H-M   'C 1 2/c 1'
_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                 109.21(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            12
_cell_length_a                   15.873(3)
_cell_length_b                   14.057(3)
_cell_length_c                   11.991(2)
_cell_measurement_reflns_used    10631
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      27.8
_cell_measurement_theta_min      3.4
_cell_volume                     2526.5(10)
_computing_cell_refinement       'PROCESS-AUTO (Rigaku, 1998)'
_computing_data_collection       'PROCESS-AUTO (Rigaku, 1998)'
_computing_data_reduction        'CrystalStructure (Rigaku/MSC, 2002)'
_computing_molecular_graphics    'ORTEP-3 for Windows (Farrugia, 1997)'
_computing_publication_material  'publCIF (Westrip, 2010)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.997
_diffrn_measured_fraction_theta_max 0.997
_diffrn_measurement_device_type  'Rigaku SCX-mini'
_diffrn_measurement_method       '\w scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0427
_diffrn_reflns_av_sigmaI/netI    0.0300
_diffrn_reflns_limit_h_max       18
_diffrn_reflns_limit_h_min       -18
_diffrn_reflns_limit_k_max       16
_diffrn_reflns_limit_k_min       -16
_diffrn_reflns_limit_l_max       14
_diffrn_reflns_limit_l_min       -14
_diffrn_reflns_number            10832
_diffrn_reflns_theta_full        25.02
_diffrn_reflns_theta_max         25.02
_diffrn_reflns_theta_min         3.41
_diffrn_standards_decay_%        0
_diffrn_standards_interval_count 0
_diffrn_standards_interval_time  0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.126
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.547
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             1224
_exptl_crystal_size_max          0.30
_exptl_crystal_size_mid          0.25
_exptl_crystal_size_min          0.20
_refine_diff_density_max         0.634
_refine_diff_density_min         -0.394
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.074
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     196
_refine_ls_number_reflns         2230
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.074
_refine_ls_R_factor_all          0.0582
_refine_ls_R_factor_gt           0.0493
_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^)+(0.0617P)^2^+3.0039P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1269
_refine_ls_wR_factor_ref         0.1330
_reflns_number_gt                1937
_reflns_number_total             2230
_reflns_threshold_expression     I>2sigma(I)
_cod_data_source_file            jj2111.cif
_cod_data_source_block           I
_cod_original_cell_volume        2526.6(9)
_cod_original_sg_symbol_H-M      'C 2/c'
_cod_database_code               2233219
_cod_database_fobs_code          2233219