Pyrazine-2,3-dicarboxylic acid
Premkumar, Thathan; Govindarajan, Subbiah; Starosta, Wojciech; Leciejewicz, Janusz; Acta Crystallographica Section E 60 (2004) o1305–o1306; doi:10.1107/S1600536804016216

data_2203988
_publ_section_title
;
 Pyrazine-2,3-dicarboxylic acid
;
_journal_issue                   8
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              o1305
_journal_page_last               o1306
_journal_paper_doi               10.1107/S1600536804016216
_journal_volume                  60
_journal_year                    2004
_chemical_formula_iupac          'C6 H4 N2 O4'
_chemical_formula_moiety         'C6 H4 N2 O4'
_chemical_formula_sum            'C6 H4 N2 O4'
_chemical_formula_weight         168.11
_chemical_name_systematic        'Pyrazine-2,3-dicarboxylic acid'
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/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                 101.69(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   7.9690(16)
_cell_length_b                   11.952(2)
_cell_length_c                   14.336(3)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    573(2)
_cell_measurement_theta_max      15
_cell_measurement_theta_min      6
_cell_volume                     1337.1(5)
_computing_cell_refinement       'KM-4 Software'
_computing_data_collection       'KM-4 Software (Kuma, 1996)'
_computing_data_reduction        'DATAPROC (Kuma, 2001)'
_computing_molecular_graphics    'XP (Siemens, 1992)'
_computing_publication_material  SHELXL97
_computing_structure_refinement  'SHELXL97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      573(2)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'Kuma KM-4 four-circle'
_diffrn_measurement_method       \w/2\q
_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  0.0508
_diffrn_reflns_av_sigmaI/netI    0.0373
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       0
_diffrn_reflns_limit_k_min       -14
_diffrn_reflns_limit_l_max       0
_diffrn_reflns_limit_l_min       -17
_diffrn_reflns_number            2528
_diffrn_reflns_theta_full        25.24
_diffrn_reflns_theta_max         25.24
_diffrn_reflns_theta_min         2.24
_diffrn_standards_decay_%        0.6
_diffrn_standards_interval_count 200
_diffrn_standards_number         2
_exptl_absorpt_coefficient_mu    0.144
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.670
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       'block (cut from a needle)'
_exptl_crystal_F_000             688
_exptl_crystal_size_max          0.24
_exptl_crystal_size_mid          0.22
_exptl_crystal_size_min          0.20
_refine_diff_density_max         0.316
_refine_diff_density_min         -0.214
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.033
_refine_ls_hydrogen_treatment    refall
_refine_ls_matrix_type           full
_refine_ls_number_parameters     249
_refine_ls_number_reflns         2423
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.033
_refine_ls_R_factor_all          0.0666
_refine_ls_R_factor_gt           0.0305
_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^)+(0.0769P)^2^] where P = (Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0962
_refine_ls_wR_factor_ref         0.1098
_reflns_number_gt                1612
_reflns_number_total             2423
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            cf6358.cif
_cod_data_source_block           I
_cod_original_sg_symbol_H-M      'P 21/c'
_cod_database_code               2203988
_cod_database_fobs_code          2203988