1,1'-Diacetyl-2,2'-biimidazole
Secondo, P. M.; Hester, C. A.; Collier, H. L.; Baughman, R. G.; Cordes, A. W.; Acta Crystallographica Section C 52 (1996) 2882–2883; doi:10.1107/S0108270196008001

data_2005622
_publ_section_title
;
 1,1'-Diacetyl-2,2'-biimidazole
;
_journal_issue                   11
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              2882
_journal_page_last               2883
_journal_paper_doi               10.1107/S0108270196008001
_journal_volume                  52
_journal_year                    1996
_chemical_formula_moiety         'C10 H10 N4 O2'
_chemical_formula_sum            'C10 H10 N4 O2'
_chemical_formula_weight         109.11
_chemical_name_systematic
;
 1,1'-diacetyl-2,2'-biimidazole
;
_space_group_IT_number           15
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-C 2yc'
_symmetry_space_group_name_H-M   'C 1 2/c 1'
_audit_creation_method           SHELXL
_cell_angle_alpha                90.00
_cell_angle_beta                 119.889(9)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   11.987(2)
_cell_length_b                   9.7183(15)
_cell_length_c                   10.2177(12)
_cell_measurement_reflns_used    50
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      18.7
_cell_measurement_theta_min      5.5
_cell_volume                     1032.0(3)
_computing_cell_refinement       'P3/P4/PC Diffractometer Program'
_computing_data_collection
'P3/P4/PC Diffractometer Program (Siemens, 1991a)'
_computing_data_reduction        'XDISK (Siemens, 1991b)'
_computing_molecular_graphics    'SHELXTL/PC (Sheldrick, 1990b)'
_computing_publication_material  'SHELXTL/PC, SHELXL93'
_computing_structure_refinement  'SHELXL93 (Sheldrick, 1993)'
_computing_structure_solution    'SHELXS86 (Sheldrick, 1990a)'
_diffrn_ambient_temperature      293(2)
_diffrn_measurement_device       'Siemens P3 diffractometer'
_diffrn_measurement_method       \q/2\q
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'normal-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0077
_diffrn_reflns_av_sigmaI/netI    0.0156
_diffrn_reflns_limit_h_max       14
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       11
_diffrn_reflns_limit_k_min       -3
_diffrn_reflns_limit_l_max       10
_diffrn_reflns_limit_l_min       -12
_diffrn_reflns_number            1090
_diffrn_reflns_theta_max         25.07
_diffrn_reflns_theta_min         2.87
_diffrn_standards_decay_%        1.1
_diffrn_standards_interval_count 50
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    0.103
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.404
_exptl_crystal_density_meas      ?
_exptl_crystal_description       'block cut from larger crystal'
_exptl_crystal_F_000             456
_exptl_crystal_size_max          0.50
_exptl_crystal_size_mid          0.38
_exptl_crystal_size_min          0.31
_refine_diff_density_max         0.185
_refine_diff_density_min         -0.129
_refine_ls_extinction_coef       0.004(2)
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_all   1.058
_refine_ls_goodness_of_fit_obs   1.100
_refine_ls_hydrogen_treatment    'riding, C-H 0.96\%A'
_refine_ls_matrix_type           full
_refine_ls_number_parameters     74
_refine_ls_number_reflns         910
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.072
_refine_ls_restrained_S_obs      1.100
_refine_ls_R_factor_all          0.0477
_refine_ls_R_factor_obs          0.0388
_refine_ls_shift/esd_max         0.000
_refine_ls_shift/esd_mean        0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w = 1/[\s^2^(Fo^2^)+(0.0614P)^2^+0.3167P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_all         0.1062
_refine_ls_wR_factor_obs         0.0998
_reflns_number_observed          778
_reflns_number_total             914
_reflns_observed_criterion       >2sigma(I)
_cod_data_source_file            ha1165.cif
_cod_data_source_block           biim2ac
_cod_depositor_comments
;
The following automatic conversions were performed:
'_symmetry_cell_setting' value 'Monoclinic' changed to 'monoclinic'
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 'Monoclinic' changed to 'monoclinic'
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 

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 'calc w =
1/[\s^2^(Fo^2^)+(0.0614P)^2^+0.3167P] where P=(Fo^2^+2Fc^2^)/3' was
changed to 'calc'. New tag '_refine_ls_weighting_details' was
created. The value of the new tag was set to 'w =
1/[\s^2^(Fo^2^)+(0.0614P)^2^+0.3167P] where P=(Fo^2^+2Fc^2^)/3'.

Automatic conversion script
Id: cif_fix_values 3143 2015-03-26 13:38:13Z robertas 
;
_cod_original_cell_volume        1032.0(2)
_cod_original_sg_symbol_H-M      'C 2/c'
_cod_database_code               2005622