The orthorhombic polymorph of pyrazine-2-carboxylic acid revisited
Małecki, Jan Grzegorz; Kruszynski, Rafal; Kusz, Joachim; Acta Crystallographica Section E 63 (2007) o3300–o3300; doi:10.1107/S1600536807030036

data_2214203
_publ_section_title
;
 The orthorhombic polymorph of pyrazine-2-carboxylic acid revisited
;
_journal_coeditor_code           GK2089
_journal_issue                   7
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              o3300
_journal_page_last               o3300
_journal_paper_doi               10.1107/S1600536807030036
_journal_volume                  63
_journal_year                    2007
_chemical_formula_iupac          'C5 H4 N2 O2'
_chemical_formula_moiety         'C5 H4 N2 O2'
_chemical_formula_sum            'C5 H4 N2 O2'
_chemical_formula_weight         124.10
_chemical_name_common
;
2-pyrazinic acid
;
_chemical_name_systematic
;
pyrazine-2-carboxylic acid
;
_space_group_IT_number           62
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  '-P 2ac 2n'
_symmetry_space_group_name_H-M   'P n m a'
_atom_sites_solution_hydrogens   mixed
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   direct
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   11.3261(18)
_cell_length_b                   6.3180(12)
_cell_length_c                   7.3389(11)
_cell_measurement_reflns_used    984
_cell_measurement_temperature    150.0(10)
_cell_measurement_theta_max      20
_cell_measurement_theta_min      3
_cell_volume                     525.16(15)
_computing_cell_refinement       'CrysAlis RED (UNILIC & Kuma, 2000)'
_computing_data_collection       'CrysAlis CCD (UNILIC & Kuma, 2000)'
_computing_data_reduction        'CrysAlis RED'
_computing_molecular_graphics
;
XP in SHELXTL/PC (Sheldrick, 1990) and ORTEP-3 (Version 1.062; Farrugia,
1997)
;
_computing_publication_material
;
SHELXL97 and PLATON (Spek, 1990)
;
_computing_structure_refinement  'SHELXL97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      150.0(10)
_diffrn_detector_area_resol_mean 1048576
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device_type  'Kuma KM-4-CCD'
_diffrn_measurement_method       \w
_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  0.0276
_diffrn_reflns_av_sigmaI/netI    0.0200
_diffrn_reflns_limit_h_max       12
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       6
_diffrn_reflns_limit_k_min       -7
_diffrn_reflns_limit_l_max       9
_diffrn_reflns_limit_l_min       -9
_diffrn_reflns_number            3291
_diffrn_reflns_theta_full        25.00
_diffrn_reflns_theta_max         25.98
_diffrn_reflns_theta_min         3.31
_diffrn_standards_decay_%        0.01
_diffrn_standards_interval_time  33.33
_diffrn_standards_number         21
_exptl_absorpt_coefficient_mu    0.125
_exptl_absorpt_correction_T_max  0.999
_exptl_absorpt_correction_T_min  0.990
_exptl_absorpt_correction_type   numerical
_exptl_absorpt_process_details   '(X-RED; Stoe & Cie, 1999)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.570
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prism
_exptl_crystal_F_000             256
_exptl_crystal_size_max          0.20
_exptl_crystal_size_mid          0.08
_exptl_crystal_size_min          0.05
_refine_diff_density_max         0.123
_refine_diff_density_min         -0.304
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.961
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     55
_refine_ls_number_reflns         561
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.961
_refine_ls_R_factor_all          0.0467
_refine_ls_R_factor_gt           0.0301
_refine_ls_shift/su_max          0.003
_refine_ls_shift/su_mean         0.001
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0564P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0775
_refine_ls_wR_factor_ref         0.0833
_reflns_number_gt                399
_reflns_number_total             561
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            gk2089.cif
_cod_data_source_block           I
_cod_database_code               2214203
_cod_database_fobs_code          2214203