Two polymorphic forms of 2,5-bis(4-methoxycarbonylphenyl)-1,3,4-oxadiazole
Reck, Günter; Orgzall, Ingo; Schulz, Burkhard; Dietzel, Birgit; Acta Crystallographica Section C 59 (2003) o634–o635; doi:10.1107/S0108270103021413

data_2013660
_publ_section_title
;
 Two polymorphic forms of
 2,5-bis(4-methoxycarbonylphenyl)-1,3,4-oxadiazole
;
_journal_issue                   11
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              o634
_journal_page_last               o635
_journal_paper_doi               10.1107/S0108270103021413
_journal_volume                  59
_journal_year                    2003
_chemical_formula_iupac          'C18 H14 N2 O5'
_chemical_formula_moiety         'C18 H14 N2 O5'
_chemical_formula_sum            'C18 H14 N2 O5'
_chemical_formula_weight         338.31
_chemical_name_common
2,5-bis(4-methoxycarbonylphenyl)-1,3,4-oxadiazole
_chemical_name_systematic
;
dimethyl 4,4'-(1,3,4-oxadiazole-2,5-diyl)diphenylenedicarboxylate
;
_space_group_IT_number           60
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  '-P 2n 2ab'
_symmetry_space_group_name_H-M   'P b c n'
_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                90.00
_cell_formula_units_Z            4
_cell_length_a                   4.7350(10)
_cell_length_b                   12.516(2)
_cell_length_c                   26.480(3)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      20
_cell_measurement_theta_min      12
_cell_volume                     1569.3(5)
_computing_cell_refinement       CAD-4
_computing_data_collection       'CAD-4 Software (Enraf--Nonius, 1977)'
_computing_data_reduction        'MoLEN (Fair, 1990)'
_computing_molecular_graphics    'SHELXTL-NT (Sheldrick, 1999)'
_computing_publication_material  SHELXL97
_computing_structure_refinement  'SHELXL97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'Enraf--Nonius CAD-4 diffractometer'
_diffrn_measurement_method       '2\q-\w scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71069
_diffrn_reflns_av_R_equivalents  0.0000
_diffrn_reflns_av_sigmaI/netI    0.0148
_diffrn_reflns_limit_h_max       5
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       14
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       31
_diffrn_reflns_limit_l_min       0
_diffrn_reflns_number            1394
_diffrn_reflns_theta_full        25.04
_diffrn_reflns_theta_max         25.04
_diffrn_reflns_theta_min         3.08
_diffrn_standards_decay_%        0.5
_diffrn_standards_interval_time  120
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    0.106
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.432
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             704
_exptl_crystal_size_max          0.42
_exptl_crystal_size_mid          0.13
_exptl_crystal_size_min          0.11
_refine_diff_density_max         0.404
_refine_diff_density_min         -0.391
_refine_ls_extinction_coef       0.0065(6)
_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   1.103
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     115
_refine_ls_number_reflns         1394
_refine_ls_number_restraints     30
_refine_ls_restrained_S_all      1.152
_refine_ls_R_factor_all          0.0562
_refine_ls_R_factor_gt           0.0498
_refine_ls_shift/su_max          0.024
_refine_ls_shift/su_mean         0.002
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.1156P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1615
_refine_ls_wR_factor_ref         0.1642
_reflns_number_gt                1052
_reflns_number_total             1394
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            na1617.cif
_cod_data_source_block           I
_cod_database_code               2013660
_cod_database_fobs_code          2013660