MultipleZ‘ in Carboxylic Acid−Pyridine Trimer Synthon and Kagomé Lattice in the Structure of 5-Methylpyrazine-2,3-dicarboxylic Acid
Babu, N. Jagadeesh; Nangia, Ashwini; Crystal Growth & Design 6 (2006) 1995–; doi:10.1021/cg060180+

data_4511516
_publ_section_title
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 MultipleZ&#x2018; in Carboxylic Acid&#x2212;Pyridine Trimer Synthon and
 Kagom\'e Lattice in the Structure of 5-Methylpyrazine-2,3-dicarboxylic
 Acid
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_journal_issue                   9
_journal_name_full               'Crystal Growth &amp; Design'
_journal_page_first              1995
_journal_paper_doi               10.1021/cg060180+
_journal_volume                  6
_journal_year                    2006
_chemical_formula_moiety         'C7 H6 N2 O4'
_chemical_formula_sum            'C7 H6 N2 O4'
_chemical_formula_weight         182.14
_chemical_name_common            'Methylpyrazine dicarboxylic acid'
_chemical_name_systematic
; 
 5-Methyl-pyrazine-2, 3-dicarboxylic acid  
;
_space_group_IT_number           170
_symmetry_cell_setting           hexagonal
_symmetry_space_group_name_Hall  'P 65'
_symmetry_space_group_name_H-M   'P 65'
_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                 90.00
_cell_angle_gamma                120.00
_cell_formula_units_Z            18
_cell_length_a                   13.6937(7)
_cell_length_b                   13.6937(7)
_cell_length_c                   21.345(2)
_cell_measurement_reflns_used    2515
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      23.14
_cell_measurement_theta_min      2.57
_cell_volume                     3466.3(4)
_computing_cell_refinement       'Bruker SMART'
_computing_data_collection       'Bruker SMART'
_computing_data_reduction        'Bruker SAINT'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      100(2)
_diffrn_measured_fraction_theta_full 0.986
_diffrn_measured_fraction_theta_max 0.986
_diffrn_measurement_device_type  'CCD area detector'
_diffrn_measurement_method       'phi and omega scans'
_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  0.0643
_diffrn_reflns_av_sigmaI/netI    0.0344
_diffrn_reflns_limit_h_max       16
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       15
_diffrn_reflns_limit_k_min       -16
_diffrn_reflns_limit_l_max       26
_diffrn_reflns_limit_l_min       -26
_diffrn_reflns_number            15628
_diffrn_reflns_theta_full        26.01
_diffrn_reflns_theta_max         26.01
_diffrn_reflns_theta_min         1.72
_exptl_absorpt_coefficient_mu    0.132
_exptl_absorpt_correction_T_max  0.9805
_exptl_absorpt_correction_T_min  0.9517
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'Bruker AXS SADABS program'
_exptl_crystal_colour            brown
_exptl_crystal_density_diffrn    1.571
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             1692
_exptl_crystal_size_max          0.38
_exptl_crystal_size_mid          0.16
_exptl_crystal_size_min          0.15
_refine_diff_density_max         0.287
_refine_diff_density_min         -0.228
_refine_diff_density_rms         0.053
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0(10)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.293
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     379
_refine_ls_number_reflns         2305
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.293
_refine_ls_R_factor_all          0.0641
_refine_ls_R_factor_gt           0.0513
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0420P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0950
_refine_ls_wR_factor_ref         0.0992
_reflns_number_gt                1985
_reflns_number_total             2305
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            cg060180%2Bsi20060630_014031.cif
_cod_data_source_block           an55_m
_cod_depositor_comments
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The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Hexagonal' changed to 'hexagonal'
according to
/usr/data/users/saulius/automatic-downloads/retrospective/ACS/lib/dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.2 from 2011-04-26.

Automatic conversion script
Id: cif_fix_values 2281 2013-09-26 08:29:07Z andrius 
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_cod_original_sg_symbol_H-M      'P6(5)  '
_cod_database_code               4511516