Hexabromo- and hexaiododisilane: small and simple molecules showing completely different crystal structures
Berger, Matthias; Auner, Norbert; Bolte, Michael; Acta Crystallographica Section C 70 (2014) 1088–1091; doi:10.1107/S2053229614022992

data_2019712
_publ_section_title
;
 Hexabromo- and hexaiododisilane: small and simple molecules showing
 completely different crystal structures
;
_journal_coeditor_code           QS3044
_journal_issue                   11
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              1088
_journal_page_last               1091
_journal_paper_doi               10.1107/S2053229614022992
_journal_volume                  70
_journal_year                    2014
_chemical_formula_iupac          'I6 Si2'
_chemical_formula_moiety         'I6 Si2'
_chemical_formula_sum            'I6 Si2'
_chemical_formula_weight         817.58
_chemical_name_systematic
;
hexaiododisilane
;
_space_group_IT_number           148
_symmetry_cell_setting           trigonal
_symmetry_space_group_name_Hall  '-R 3'
_symmetry_space_group_name_H-M   'R -3 :H'
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL97
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                120.00
_cell_formula_units_Z            3
_cell_length_a                   7.1436(9)
_cell_length_b                   7.1436(9)
_cell_length_c                   22.213(3)
_cell_measurement_reflns_used    1398
_cell_measurement_temperature    173(2)
_cell_measurement_theta_max      27.7
_cell_measurement_theta_min      3.4
_cell_volume                     981.7(2)
_computing_cell_refinement
;
X-AREA (Stoe & Cie, 2001)
;
_computing_data_collection
;
X-AREA (Stoe & Cie, 2001)
;
_computing_data_reduction
;
X-AREA (Stoe & Cie, 2001)
;
_computing_molecular_graphics
;
XP (Sheldrick, 2008)
;
_computing_publication_material
;
SHELXL97 (Sheldrick, 2008) and publCIF (Westrip, 2010)
;
_computing_structure_refinement
;
SHELXL97 (Sheldrick, 2008)
;
_computing_structure_solution
;
SHELXS97 (Sheldrick, 2008)
;
_diffrn_ambient_temperature      173(2)
_diffrn_measured_fraction_theta_full 0.997
_diffrn_measured_fraction_theta_max 0.994
_diffrn_measurement_device_type  'Stoe IPDS II two-circle'
_diffrn_measurement_method       \w
_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  0.0532
_diffrn_reflns_av_sigmaI/netI    0.0394
_diffrn_reflns_limit_h_max       5
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       -8
_diffrn_reflns_limit_l_max       25
_diffrn_reflns_limit_l_min       -28
_diffrn_reflns_number            1409
_diffrn_reflns_theta_full        25.00
_diffrn_reflns_theta_max         27.43
_diffrn_reflns_theta_min         3.42
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    14.363
_exptl_absorpt_correction_T_max  0.1524
_exptl_absorpt_correction_T_min  0.1442
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
[MULABS (Spek, 2009; Blessing, 1995)]
;
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    4.149
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             1038
_exptl_crystal_size_max          0.22
_exptl_crystal_size_mid          0.22
_exptl_crystal_size_min          0.21
_refine_diff_density_max         1.456
_refine_diff_density_min         -1.571
_refine_ls_extinction_coef       0.0055(6)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method
;
SHELXL97 (Sheldrick, 2008)
;
_refine_ls_goodness_of_fit_ref   1.049
_refine_ls_matrix_type           full
_refine_ls_number_parameters     14
_refine_ls_number_reflns         500
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.049
_refine_ls_R_factor_all          0.0510
_refine_ls_R_factor_gt           0.0470
_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^)+(0.0824P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1211
_refine_ls_wR_factor_ref         0.1234
_reflns_number_gt                438
_reflns_number_total             500
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            qs3044sup1.cif
_cod_data_source_block           au116
_cod_depositor_comments
'Adding full bibliography for 2019711--2019712.cif.'
_cod_original_cell_volume        981.70(10)
_cod_original_sg_symbol_H-M      R-3
_cod_database_code               2019712
_cod_database_fobs_code          2019712