2-(1,3-Dibenzylimidazolidin-2-ylidene)malononitrile
Feng, Xiao-Zhong; Yan, Fu-Feng; Li, Zhen-Ping; Acta Crystallographica Section E 64 (2008) o1120–; doi:10.1107/S1600536808014025

data_2218428
_publ_section_title
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 2-(1,3-Dibenzylimidazolidin-2-ylidene)malononitrile
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_journal_coeditor_code           HG2400
_journal_issue                   6
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              o1120
_journal_paper_doi               10.1107/S1600536808014025
_journal_volume                  64
_journal_year                    2008
_chemical_formula_iupac          'C20 H18 N4'
_chemical_formula_moiety         'C20 H18 N4'
_chemical_formula_sum            'C20 H18 N4'
_chemical_formula_weight         314.38
_chemical_name_systematic
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2-(1,3-Dibenzylimidazolidin-2-ylidene)malononitrile
;
_space_group_IT_number           29
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'P 2c -2ac'
_symmetry_space_group_name_H-M   'P c a 21'
_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                   15.445(3)
_cell_length_b                   9.753(2)
_cell_length_c                   11.411(2)
_cell_measurement_reflns_used    2422
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      25.11
_cell_measurement_theta_min      2.27
_cell_volume                     1718.9(6)
_computing_cell_refinement       'RAPID-AUTO (Rigaku, 2004)'
_computing_data_collection       'RAPID-AUTO (Rigaku, 2004)'
_computing_data_reduction        'RAPID-AUTO (Rigaku, 2004)'
_computing_molecular_graphics    'SHELXTL (Sheldrick, 2008)'
_computing_publication_material  'SHELXTL (Sheldrick, 2008)'
_computing_structure_refinement  'SHELXTL (Sheldrick, 2008)'
_computing_structure_solution    'SHELXTL (Sheldrick, 2008)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.998
_diffrn_measurement_device_type  'Rigaku R-AXIS RAPID IP area-detector'
_diffrn_measurement_method       '\w oscillation'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'Rotating Anode'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0379
_diffrn_reflns_av_sigmaI/netI    0.0200
_diffrn_reflns_limit_h_max       18
_diffrn_reflns_limit_h_min       -18
_diffrn_reflns_limit_k_max       11
_diffrn_reflns_limit_k_min       -11
_diffrn_reflns_limit_l_max       13
_diffrn_reflns_limit_l_min       -12
_diffrn_reflns_number            12952
_diffrn_reflns_theta_full        25.00
_diffrn_reflns_theta_max         25.00
_diffrn_reflns_theta_min         3.05
_diffrn_standards_decay_%        0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.074
_exptl_absorpt_correction_T_max  0.9941
_exptl_absorpt_correction_T_min  0.9824
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '(ABSCOR; Higashi, 1995)'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.215
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             664
_exptl_crystal_size_max          0.24
_exptl_crystal_size_mid          0.14
_exptl_crystal_size_min          0.08
_refine_diff_density_max         0.167
_refine_diff_density_min         -0.154
_refine_ls_extinction_coef       0.028(3)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     'SHELXTL (Sheldrick, 2008)'
_refine_ls_goodness_of_fit_ref   1.127
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     218
_refine_ls_number_reflns         1607
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.127
_refine_ls_R_factor_all          0.0547
_refine_ls_R_factor_gt           0.0411
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0488P)^2^+0.3923P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0933
_refine_ls_wR_factor_ref         0.1144
_reflns_number_gt                1291
_reflns_number_total             1607
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            hg2400.cif
_cod_data_source_block           I
_cod_depositor_comments
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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 
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_cod_database_code               2218428
_cod_database_fobs_code          2218428