An orthorhombic polymorph of <i>N</i>,<i>N</i>'-bis(2-pyridylmethyl)pyrazine-2,3-dicarboxamide
Dilovan S. Cati; Helen Stoeckli-Evans; Acta Crystallographica Section E 60 (2004) o210–o212; doi:10.1107/S160053680400008X

data_2203174
_publ_section_title
;
 An orthorhombic polymorph of
 <i>N</i>,<i>N</i>'-bis(2-pyridylmethyl)pyrazine-2,3-dicarboxamide
;
_journal_issue                   2
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              o210
_journal_page_last               o212
_journal_paper_doi               10.1107/S160053680400008X
_journal_volume                  60
_journal_year                    2004
_chemical_formula_iupac          'C18 H16 N6 O2'
_chemical_formula_moiety         'C18 H16 N6 O2'
_chemical_formula_sum            'C18 H16 N6 O2'
_chemical_formula_weight         348.37
_space_group_IT_number           61
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  '-P 2ac 2ab'
_symmetry_space_group_name_H-M   'P b c a'
_atom_sites_solution_hydrogens   difmap
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            8
_cell_length_a                   8.5131(6)
_cell_length_b                   31.862(2)
_cell_length_c                   12.1757(6)
_cell_measurement_reflns_used    15934
_cell_measurement_temperature    153
_cell_measurement_theta_max      25.61
_cell_measurement_theta_min      1.28
_cell_volume                     3302.6(4)
_computing_cell_refinement       X-AREA
_computing_data_collection       'X-AREA (Stoe & Cie, 2003)'
_computing_data_reduction        'X-RED32 Stoe & Cie, 2003)'
_computing_molecular_graphics    'PLATON  (Spek, 1990)'
_computing_publication_material  SHELXL97
_computing_structure_refinement  'SHELXL97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      153
_diffrn_measured_fraction_theta_full 0.982
_diffrn_measured_fraction_theta_max 0.982
_diffrn_measurement_device_type  'Stoe IPDS-II'
_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  0.0450
_diffrn_reflns_av_sigmaI/netI    0.0269
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       -10
_diffrn_reflns_limit_k_max       38
_diffrn_reflns_limit_k_min       -38
_diffrn_reflns_limit_l_max       14
_diffrn_reflns_limit_l_min       -14
_diffrn_reflns_number            18389
_diffrn_reflns_reduction_process ' ?'
_diffrn_reflns_theta_full        25.53
_diffrn_reflns_theta_max         25.53
_diffrn_reflns_theta_min         1.28
_diffrn_standards_decay_%        0
_diffrn_standards_interval_time  0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.097
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.401
_exptl_crystal_density_method    'Not Measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             1456
_exptl_crystal_size_max          0.500
_exptl_crystal_size_mid          0.500
_exptl_crystal_size_min          0.400
_refine_diff_density_max         0.171
_refine_diff_density_min         -0.140
_refine_ls_extinction_coef       0.0087(9)
_refine_ls_extinction_expression FC^*^=KFC[1+0.001XFC^2^\L^3^/SIN(2\Q)]^-1/4^
_refine_ls_extinction_method     shelxl97
_refine_ls_goodness_of_fit_ref   1.033
_refine_ls_hydrogen_treatment    refall
_refine_ls_matrix_type           full
_refine_ls_number_parameters     300
_refine_ls_number_reflns         3034
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.033
_refine_ls_R_factor_all          0.0437
_refine_ls_R_factor_gt           0.0315
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.001
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0478P)^2^+0.1168P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0744
_refine_ls_wR_factor_ref         0.0785
_reflns_number_gt                2456
_reflns_number_total             3034
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            cv6257.cif
_cod_data_source_block           I
_cod_depositor_comments
;
The following automatic conversions were performed:
'_symmetry_cell_setting' value 'Orthorhombic' changed to 'orthorhombic'
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 'Orthorhombic' changed to
'orthorhombic' 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_database_code               2203174
_cod_database_fobs_code          2203174