Four polymorphs (polytypes) of 5,6-dimethylbenzofurazan 1-oxide
Britton, Doyle; Young, Jr, Victor G.; Noland, Wayland E.; Pinnow, Matthew J.; Clark, Christopher M.; Acta Crystallographica Section B 68 (2012) 536–542; doi:10.1107/S0108768112037457

data_2105260
_publ_section_title
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 Four polymorphs (polytypes) of 5,6-dimethylbenzofurazan 1-oxide
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_journal_issue                   5
_journal_name_full               'Acta Crystallographica Section B'
_journal_page_first              536
_journal_page_last               542
_journal_paper_doi               10.1107/S0108768112037457
_journal_volume                  68
_journal_year                    2012
_chemical_formula_moiety         'C10 H8 O3'
_chemical_formula_sum            'C10 H8 O3'
_chemical_formula_weight         176.16
_chemical_name_systematic
;
 4,5-dimethylphthalic anhydride
;
_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   calc
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXTL
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   11.744(4)
_cell_length_b                   7.601(3)
_cell_length_c                   18.102(6)
_cell_measurement_reflns_used    3420
_cell_measurement_temperature    173(2)
_cell_measurement_theta_max      27.5
_cell_measurement_theta_min      2.8
_cell_volume                     1615.9(10)
_computing_cell_refinement       'SAINT (Bruker, 2003)'
_computing_data_collection       'SMART (Bruker, 2003)'
_computing_data_reduction        SAINT
_computing_molecular_graphics    SHELXTL
_computing_publication_material  SHELXTL
_computing_structure_refinement  SHELXTL
_computing_structure_solution    'SHELXTL (Sheldrick, 2008)'
_diffrn_ambient_temperature      173(2)
_diffrn_measured_fraction_theta_full 0.997
_diffrn_measured_fraction_theta_max 0.997
_diffrn_measurement_device_type
;
Bruker SMART 1K CCD area-detector diffractometer
;
_diffrn_measurement_method       '\w 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  0.0266
_diffrn_reflns_av_sigmaI/netI    0.0127
_diffrn_reflns_limit_h_max       15
_diffrn_reflns_limit_h_min       -15
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       -9
_diffrn_reflns_limit_l_max       23
_diffrn_reflns_limit_l_min       -23
_diffrn_reflns_number            17411
_diffrn_reflns_theta_full        27.54
_diffrn_reflns_theta_max         27.54
_diffrn_reflns_theta_min         2.25
_diffrn_standards_decay_%        'less than 1'
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.108
_exptl_absorpt_correction_T_max  0.97
_exptl_absorpt_correction_T_min  0.95
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
SADABS; Sheldrick, 2008; Blessing, 1995
;
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.448
_exptl_crystal_density_meas      ?
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prism
_exptl_crystal_F_000             736
_exptl_crystal_size_max          .50
_exptl_crystal_size_mid          .35
_exptl_crystal_size_min          .25
_refine_diff_density_max         0.327
_refine_diff_density_min         -0.140
_refine_ls_extinction_coef       0.084(4)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   1.055
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     121
_refine_ls_number_reflns         1857
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.055
_refine_ls_R_factor_all          0.0347
_refine_ls_R_factor_gt           0.0333
_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^)+(0.0550P)^2^+0.4380P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0972
_refine_ls_wR_factor_ref         0.0986
_reflns_number_gt                1772
_reflns_number_total             1857
_reflns_threshold_expression     '>2\s(I) '
_cod_data_source_file            ps5015.cif
_cod_data_source_block           Me2PA
_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 
;
_cod_original_sg_symbol_H-M      Pbca
_cod_database_code               2105260
_cod_database_fobs_code          2105260