α,α'-Bis(2-pyridylseleno)-<i>p</i>-xylene
Kienitz, C. O.; Thöne, C.; Jones, P. G.; Acta Crystallographica Section C 52 (1996) 2847–2849; doi:10.1107/S0108270196007536

data_2005618
_publ_section_title
;
 \a,\a'-Bis(2-pyridylseleno)-<i>p</i>-xylene
;
_journal_issue                   11
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              2847
_journal_page_last               2849
_journal_paper_doi               10.1107/S0108270196007536
_journal_volume                  52
_journal_year                    1996
_chemical_formula_sum            'C18 H16 N2 Se2'
_chemical_formula_weight         418.25
_chemical_name_systematic
;
 \a,\a'-Bis(2-selenopyridine)-p-xylene
;
_chemical_temperature_decomposition 66
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/c 1'
_audit_creation_method           SHELXL
_cell_angle_alpha                90.00
_cell_angle_beta                 96.12(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   11.628(3)
_cell_length_b                   6.804(2)
_cell_length_c                   20.778(5)
_cell_measurement_reflns_used    58
_cell_measurement_temperature    143(2)
_cell_measurement_theta_max      11.5
_cell_measurement_theta_min      10
_cell_volume                     1634.5(8)
_computing_cell_refinement       DIF4
_computing_data_collection       'DIF4 (Stoe & Cie, 1994a)'
_computing_data_reduction        'REDU4 (Stoe & Cie, 1994b)'
_computing_molecular_graphics    'XP5 (Siemens, 1994b)'
_computing_publication_material  SHELXL93
_computing_structure_refinement  'SHELXL93 (Sheldrick, 1993)'
_computing_structure_solution    'SHELXS86 (Sheldrick, 1990)'
_diffrn_ambient_temperature      143(2)
_diffrn_measurement_device       'Stoe STADI-4'
_diffrn_measurement_method       \w/\q-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  0.0240
_diffrn_reflns_av_sigmaI/netI    0.0285
_diffrn_reflns_limit_h_max       1
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       8
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       24
_diffrn_reflns_limit_l_min       -24
_diffrn_reflns_number            3123
_diffrn_reflns_theta_max         25.03
_diffrn_reflns_theta_min         3.15
_diffrn_standards_decay_%        0
_diffrn_standards_interval_time  60
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    4.521
_exptl_absorpt_correction_T_max  .985
_exptl_absorpt_correction_T_min  .709
_exptl_absorpt_correction_type   '\y scans (XEMP; Siemens, 1994a)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.700
_exptl_crystal_density_meas      ?
_exptl_crystal_description       'irregular needle'
_exptl_crystal_F_000             824
_exptl_crystal_size_max          0.80
_exptl_crystal_size_mid          0.15
_exptl_crystal_size_min          0.10
_refine_diff_density_max         0.385
_refine_diff_density_min         -0.532
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_all   1.067
_refine_ls_goodness_of_fit_obs   1.056
_refine_ls_hydrogen_treatment    riding
_refine_ls_matrix_type           full
_refine_ls_number_parameters     199
_refine_ls_number_reflns         2856
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.134
_refine_ls_restrained_S_obs      1.056
_refine_ls_R_factor_all          0.0451
_refine_ls_R_factor_obs          0.0313
_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^)+(0.0339P)^2^+1.3872P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_all         0.0850
_refine_ls_wR_factor_obs         0.0699
_reflns_number_observed          2270
_reflns_number_total             2869
_reflns_observed_criterion       >2sigma(I)
_cod_data_source_file            fg1204.cif
_cod_data_source_block           berta
_cod_depositor_comments
;
The following automatic conversions were performed:

'_chemical_melting_point' tag was changed to
'_chemical_temperature_decomposition' since the value had been '66
(dec.)'. The value '66 (dec.)' was changed to '66'.

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^)+(0.0339P)^2^+1.3872P] 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^)+(0.0339P)^2^+1.3872P] 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        1634.6(8)
_cod_original_sg_symbol_H-M      'P 21/c'
_cod_database_code               2005618