Structural isomerism in (p-XC(6)H(4))SeCl(3) and (p-XC(6)H(4))SeBr(3) (X = F, Cl) compounds. Co-crystallisation of cis- and trans-dimeric forms of (p-ClC(6)H(4))SeCl(2)(μ-Cl)(2)(p-ClC(6)H(4))SeCl(2). A new structural modification for the "PhSeBr" reagent, Ph(2)Se(2)Br(2), containing an elongated Se-Se bond.
Barnes, Nicholas A.; Godfrey, Stephen M.; Ollerenshaw, Ruth T. A.; Khan, Rana Z.; Pritchard, Robin G.; Dalton transactions (Cambridge, England : 2003) 41 (2012) 14583–14593; doi:10.1039/c2dt31539d

data_7020428
_publ_section_title
;
 Structural isomerism in (p-XC(6)H(4))SeCl(3) and (p-XC(6)H(4))SeBr(3) (X
 = F, Cl) compounds. Co-crystallisation of cis- and trans-dimeric forms of
 (p-ClC(6)H(4))SeCl(2)(\m-Cl)(2)(p-ClC(6)H(4))SeCl(2). A new structural
 modification for the &quot;PhSeBr&quot; reagent, Ph(2)Se(2)Br(2),
 containing an elongated Se-Se bond.
;
_journal_issue                   48
_journal_name_full
'Dalton transactions (Cambridge, England : 2003)'
_journal_page_first              14583
_journal_page_last               14593
_journal_paper_doi               10.1039/c2dt31539d
_journal_volume                  41
_journal_year                    2012
_chemical_absolute_configuration ad
_chemical_compound_source        'synthesis as described'
_chemical_formula_moiety         'C12 H10 Br2 Se2'
_chemical_formula_sum            'C12 H10 Br2 Se2'
_chemical_formula_weight         471.94
_space_group_IT_number           4
_symmetry_cell_setting           monoclinic
_symmetry_Int_Tables_number      4
_symmetry_space_group_name_Hall  'P 2yb'
_symmetry_space_group_name_H-M   'P 1 21 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_conform_dict_location     ftp://ftp.iucr.org/pub/cif_core.dic
_audit_conform_dict_name         cif_core.dic
_audit_conform_dict_version      2.4
_audit_creation_date             2012-07-04T11:05:51-00:00
_audit_creation_method           'WinGX routine CIF_UPDATE'
_audit_update_record
;
2012-09-11 # Formatted by publCIF
;
_cell_angle_alpha                90.000(4)
_cell_angle_beta                 90.004(4)
_cell_angle_gamma                90.000(7)
_cell_formula_units_Z            2
_cell_length_a                   6.0108(5)
_cell_length_b                   7.1843(7)
_cell_length_c                   15.6165(18)
_cell_measurement_reflns_used    1703
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      27
_cell_measurement_theta_min      2
_cell_measurement_wavelength     0.71073
_cell_volume                     674.37(12)
_computing_cell_refinement       'HKL Scalepack (Otwinowski & Minor 1997)'
_computing_data_collection       'Collect (Nonius BV, 1997-2000)'
_computing_data_reduction
'HKL Denzo and Scalepack (Otwinowski & Minor 1997)'
_computing_molecular_graphics    'Ortep-3 for Windows (Farrugia, 1997)'
_computing_publication_material  'WinGX publication routines (Farrugia, 1999)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_solution    'SIR92 (Giacovazzo et al, 1993)'
_diffrn_ambient_temperature      100(2)
_diffrn_detector                 'CCD plate'
_diffrn_detector_area_resol_mean 9
_diffrn_measured_fraction_theta_full 0.984
_diffrn_measured_fraction_theta_max 0.984
_diffrn_measurement_device       '95mm CCD camera on \k-goniostat'
_diffrn_measurement_device_type  KappaCCD
_diffrn_measurement_method       'CCD rotation images, thick slices'
_diffrn_orient_matrix_type       'by Nonius Collect from scalepack cell'
_diffrn_orient_matrix_UB_11      -0.142683
_diffrn_orient_matrix_UB_12      0.59124E-2
_diffrn_orient_matrix_UB_13      0.328272E-1
_diffrn_orient_matrix_UB_21      -0.854461E-1
_diffrn_orient_matrix_UB_22      -0.28603E-2
_diffrn_orient_matrix_UB_23      -0.549223E-1
_diffrn_orient_matrix_UB_31      -0.43096E-2
_diffrn_orient_matrix_UB_32      -0.139037
_diffrn_orient_matrix_UB_33      0.25258E-2
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.158
_diffrn_reflns_av_unetI/netI     0.0983
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_k_max       6
_diffrn_reflns_limit_k_min       -8
_diffrn_reflns_limit_l_max       18
_diffrn_reflns_limit_l_min       -18
_diffrn_reflns_number            5484
_diffrn_reflns_reduction_process
;
Scaled and merged with Sortav
R.H. Blessing, (1987) Cryst. Rev. 1, 3-58
R.H. Blessing, (1989) J. Appl. Cryst. 22, 396-397
;
_diffrn_reflns_theta_full        25.6
_diffrn_reflns_theta_max         25.6
_diffrn_reflns_theta_min         3.63
_diffrn_source                   'Enraf Nonius FR590'
_exptl_absorpt_coefficient_mu    11.378
_exptl_absorpt_correction_T_max  0.6
_exptl_absorpt_correction_T_min  0.3422
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
Blessing, R. H. (1995) Acta Cryst., A51, 33-38.
;
_exptl_crystal_colour            purple
_exptl_crystal_density_diffrn    2.324
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prism
_exptl_crystal_F_000             440
_exptl_crystal_size_max          0.12
_exptl_crystal_size_mid          0.05
_exptl_crystal_size_min          0.05
_refine_diff_density_max         2.487
_refine_diff_density_min         -2.202
_refine_diff_density_rms         0.364
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.18(14)
_refine_ls_extinction_coef       0.003(2)
_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   1.068
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     147
_refine_ls_number_reflns         2061
_refine_ls_number_restraints     85
_refine_ls_restrained_S_all      1.048
_refine_ls_R_factor_all          0.1222
_refine_ls_R_factor_gt           0.0886
_refine_ls_shift/su_max          0.004
_refine_ls_shift/su_mean         0
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.1203P)^2^+28.2540P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.213
_refine_ls_wR_factor_ref         0.2544
_reflns_number_gt                1646
_reflns_number_total             2061
_reflns_threshold_expression     >2\s(I)
_cod_data_source_file            c2dt31539d.txt
_cod_data_source_block           r_Ph2Se2Br2
_cod_original_sg_symbol_H-M      'P 21'
_cod_database_code               7020428