An Orthorhombic Polymorph of 2,2'-Dipyridyl Diselenide
Dunne, Simon, J.; von Nagy-Felsobuki, Ellak, I.; Mackay, Maureen, F.; Acta Crystallographica Section C 54 (1998) 887–889; doi:10.1107/S0108270197018118

data_2007394
_publ_section_title
;
 An Orthorhombic Polymorph of 2,2'-Dipyridyl Diselenide
;
_journal_issue                   6
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              887
_journal_page_last               889
_journal_paper_doi               10.1107/S0108270197018118
_journal_volume                  54
_journal_year                    1998
_chemical_formula_structural     'C10 H8 N2 Se2'
_chemical_formula_sum            'C10 H8 N2 Se2'
_chemical_formula_weight         314.1
_chemical_melting_point          323.8(8)
_space_group_IT_number           33
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'P 2c -2n'
_symmetry_space_group_name_H-M   'P n a 21'
_audit_creation_method           'SHELXL-93 (Sheldrick, 1993)'
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   17.492(4)
_cell_length_b                   10.839(2)
_cell_length_c                   5.7530(10)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      30
_cell_measurement_theta_min      21
_cell_volume                     1090.7(4)
_computing_cell_refinement       'Rigaku AFC Software'
_computing_data_collection
'Rigaku AFC Software (Rigaku Corporation, 1974)'
_computing_data_reduction        'Rigaku AFC Software'
_computing_molecular_graphics    'ORTEPII (Johnson, 1976)'
_computing_publication_material  SHELXL93
_computing_structure_refinement  'SHELXL-93 (Sheldrick, 1993)'
_computing_structure_solution    'SHELX76 (Sheldrick, 1976)'
_diffrn_ambient_temperature      293(2)
_diffrn_measurement_device       'Rigaku AFC diffractometer'
_diffrn_measurement_method       \w/2\q
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.5418
_diffrn_reflns_av_R_equivalents  0.0
_diffrn_reflns_limit_h_max       20
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       6
_diffrn_reflns_limit_l_min       0
_diffrn_reflns_number            1021
_diffrn_reflns_theta_max         65.00
_diffrn_reflns_theta_min         4.80
_diffrn_standards_decay_%        0.65
_diffrn_standards_interval_count 50
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    8.16
_exptl_absorpt_correction_T_max  0.3108
_exptl_absorpt_correction_T_min  0.0667
_exptl_absorpt_correction_type   'Gaussian (SHELX76; Sheldrick, 1976)'
_exptl_crystal_colour            'pale yellow'
_exptl_crystal_density_diffrn    1.913
_exptl_crystal_density_meas      ?
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       tabular
_exptl_crystal_F_000             600
_exptl_crystal_size_max          0.462
_exptl_crystal_size_mid          0.359
_exptl_crystal_size_min          0.180
_refine_diff_density_max         0.441
_refine_diff_density_min         -0.607
_refine_ls_abs_structure_details 'Flack (1983)'
_refine_ls_abs_structure_Flack   0.00(6)
_refine_ls_extinction_coef       0.0131(8)
_refine_ls_extinction_method     'SHELXL93 (Sheldrick, 1993)'
_refine_ls_goodness_of_fit_all   1.108
_refine_ls_goodness_of_fit_obs   1.124
_refine_ls_hydrogen_treatment    refU
_refine_ls_matrix_type           full
_refine_ls_number_parameters     127
_refine_ls_number_reflns         1021
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.108
_refine_ls_restrained_S_obs      1.124
_refine_ls_R_factor_all          0.0331
_refine_ls_R_factor_obs          .0321
_refine_ls_shift/esd_max         0.003
_refine_ls_shift/esd_mean        0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w = 1/[\s^2^(Fo^2^)+(0.0590P)^2^+0.6984P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_all         0.0878
_refine_ls_wR_factor_obs         .0867
_reflns_number_observed          975
_reflns_number_total             1021
_reflns_observed_criterion       >2sigma(I)
_cod_data_source_file            ta1189.cif
_cod_data_source_block           Componnd_1
_cod_depositor_comments
;
The following automatic conversions were performed:

'_chemical_melting_point' value '323-324.5' was changed to '323.8(8)'
- the average value was taken and precision was estimated.

Automatic conversion script
Id: cif_fix_values 1646 2011-03-28 12:23:43Z adriana 

The following automatic conversions were performed:

'_chemical_melting_point' value '323-324.5' was changed to '323.8(8)'
- the average value was taken and precision was estimated.

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^)+(0.0590P)^2^+0.6984P] 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^)+(0.0590P)^2^+0.6984P] where P=(Fo^2^+2Fc^2^)/3'.

Automatic conversion script
Id: cif_fix_values 3143 2015-03-26 13:38:13Z robertas 
;
_cod_database_code               2007394