3-Aminopyrazine-2-carboxylic Acid
A. J. Dobson; R. E. Gerkin; Acta Crystallographica Section C 52 (1996) 1512–1514; doi:10.1107/S0108270195016416

data_2004980
_publ_section_title
;
 3-Aminopyrazine-2-carboxylic Acid
;
_journal_coeditor_code           FG1125
_journal_issue                   6
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              1512
_journal_page_last               1514
_journal_paper_doi               10.1107/S0108270195016416
_journal_volume                  52
_journal_year                    1996
_chemical_formula_iupac          'C5 H5 N3 O2'
_chemical_formula_moiety         'C5 H5 N3 O2 '
_chemical_formula_sum            'C5 H5 N3 O2'
_chemical_formula_weight         139.11
_chemical_name_common            '3-aminopyrazine-2-carboxylic 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'
_cell_angle_alpha                90.
_cell_angle_beta                 99.18(1)
_cell_angle_gamma                90.
_cell_formula_units_Z            4
_cell_length_a                   3.756(1)
_cell_length_b                   14.191(1)
_cell_length_c                   10.911(1)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    296
_cell_measurement_theta_max      16.5
_cell_measurement_theta_min      11.7
_cell_volume                     574.12(17)
_computing_cell_refinement       'MSC/AFC Diffractometer Control Software'
_computing_data_collection
;
MSC/AFC Diffractometer Control Software
(Molecular Structure Corporation, 1988)
;
_computing_data_reduction
'TEXSAN (Molecular Structure Corporation, 1989)'
_computing_molecular_graphics    'ORTEPII (Johnson, 1976)'
_computing_publication_material  TEXSAN
_computing_structure_refinement  TEXSAN
_computing_structure_solution    'SHELXS86 (Sheldrick, 1985)'
_diffrn_ambient_temperature      296
_diffrn_measurement_device       'Rigaku AFC5S'
_diffrn_measurement_method       \w
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'X-ray tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.013
_diffrn_reflns_limit_h_max       4
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       18
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       14
_diffrn_reflns_limit_l_min       -14
_diffrn_reflns_number            1582
_diffrn_reflns_theta_max         27.50
_diffrn_reflns_theta_min         2.00
_diffrn_standards_decay_%        2.70
_diffrn_standards_interval_count 150
_diffrn_standards_number         6
_exptl_absorpt_coefficient_mu    0.120
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.609
_exptl_crystal_density_meas      ?
_exptl_crystal_description       'cut plate'
_exptl_crystal_F_000             288
_exptl_crystal_size_max          0.35
_exptl_crystal_size_mid          0.31
_exptl_crystal_size_min          0.16
_refine_diff_density_max         0.27
_refine_diff_density_min         -0.16
_refine_ls_extinction_coef       2.2E-6(2)
_refine_ls_extinction_method     'Zachariasen (1963, 1968)'
_refine_ls_goodness_of_fit_obs   1.80
_refine_ls_hydrogen_treatment
;
H atoms: C---H riding (0.98\%A) and all parameters refined for
O---H and N---H
;
_refine_ls_matrix_type           full
_refine_ls_number_parameters     104
_refine_ls_number_reflns         936
_refine_ls_R_factor_obs          0.045
_refine_ls_shift/esd_max         <0.01
_refine_ls_structure_factor_coef F
_refine_ls_weighting_details     'w = 1/\s~F~^2^'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_obs         0.053
_reflns_number_observed          936
_reflns_number_total             1381
_reflns_observed_criterion       I>3\s~I~
_cod_data_source_file            fg1125.cif
_cod_data_source_block           A
_cod_depositor_comments
;
The following automatic conversions were performed:

'_exptl_crystal_density_meas' value 'not measured' was changed to '?'
- the value is perceived as not measured.

Automatic conversion script
Id: cif_fix_values 3008 2015-01-20 13:52:24Z robertas 

The following automatic conversions were performed:

'_refine_ls_weighting_scheme' value 'w = 1/\s~F~^2^' was changed to
'calc'. New tag '_refine_ls_weighting_details' was created. The value
of the new tag was set to 'w = 1/\s~F~^2^'.

Automatic conversion script
Id: cif_fix_values 3143 2015-03-26 13:38:13Z robertas 
;
_cod_original_cell_volume        574.10(10)
_cod_original_sg_symbol_H-M      'P 21/c'
_cod_database_code               2004980