A monoclinic polymorph of pyrazinic acid
Shi, Xue-Fang; Wu, Li; Xing, Zhi-Yong; Acta Crystallographica Section E 62 (2006) o15–o17; doi:10.1107/S160053680503953X

data_2207725
_publ_section_title
;
 A monoclinic polymorph of pyrazinic acid
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_journal_coeditor_code           BH6050
_journal_issue                   1
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              o15
_journal_page_last               o17
_journal_paper_doi               10.1107/S160053680503953X
_journal_volume                  62
_journal_year                    2006
_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            'pyrazinic acid'
_chemical_name_systematic        'pyrazine-2-carboxylic acid'
_space_group_IT_number           4
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  'P 2yb'
_symmetry_space_group_name_H-M   'P 1 21 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_cell_angle_alpha                90.00
_cell_angle_beta                 91.936(7)
_cell_angle_gamma                90.00
_cell_formula_units_Z            2
_cell_length_a                   3.7249(14)
_cell_length_b                   11.281(4)
_cell_length_c                   6.298(2)
_cell_measurement_reflns_used    477
_cell_measurement_temperature    294(2)
_cell_measurement_theta_max      23.72
_cell_measurement_theta_min      3.54
_cell_volume                     264.49(16)
_computing_cell_refinement       'SAINT (Bruker, 1997)'
_computing_data_collection       'SMART (Bruker, 1997)'
_computing_data_reduction        SAINT
_computing_molecular_graphics    'SHELXTL (Bruker, 1997)'
_computing_publication_material  SHELXTL
_computing_structure_refinement  'SHELXL97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      294(2)
_diffrn_measured_fraction_theta_full 0.993
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'Bruker SMART CCD area-detector'
_diffrn_measurement_method       '\f and \w'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0373
_diffrn_reflns_av_sigmaI/netI    0.0425
_diffrn_reflns_limit_h_max       4
_diffrn_reflns_limit_h_min       -4
_diffrn_reflns_limit_k_max       6
_diffrn_reflns_limit_k_min       -14
_diffrn_reflns_limit_l_max       7
_diffrn_reflns_limit_l_min       -7
_diffrn_reflns_number            1501
_diffrn_reflns_theta_full        25.00
_diffrn_reflns_theta_max         26.50
_diffrn_reflns_theta_min         3.24
_diffrn_standards_decay_%        0
_diffrn_standards_interval_count 0
_diffrn_standards_interval_time  0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.124
_exptl_absorpt_correction_T_max  0.988
_exptl_absorpt_correction_T_min  0.962
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '(SADABS; Sheldrick, 1996)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.558
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             128
_exptl_crystal_size_max          0.30
_exptl_crystal_size_mid          0.16
_exptl_crystal_size_min          0.10
_refine_diff_density_max         0.138
_refine_diff_density_min         -0.180
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.070
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
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_refine_ls_restrained_S_all      1.069
_refine_ls_R_factor_all          0.0609
_refine_ls_R_factor_gt           0.0372
_refine_ls_shift/su_max          0.002
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0320P)^2^+0.0353P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0690
_refine_ls_wR_factor_ref         0.0791
_reflns_number_gt                440
_reflns_number_total             571
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            bh6050.cif
_cod_data_source_block           I
_cod_depositor_comments
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The following automatic conversions were performed:
'_symmetry_cell_setting' value 'Monoclinic' changed to 'monoclinic'
according to '/home/saulius/struct/CIF-dictionaries/cif_core.dic'
dictionary named 'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_enum 1527 2010-12-29 10:47:43Z saulius 

The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Monoclinic' changed to 'monoclinic'
according to /home/saulius/struct/CIF-dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_values 1715 2011-07-08 13:25:40Z adriana 
;
_cod_original_cell_volume        264.48(18)
_cod_original_sg_symbol_H-M      'P 21'
_cod_database_code               2207725
_cod_database_fobs_code          2207725