Isomeric Metamorphosis: Si3E (E = S, Se, and Te) Bicyclo[1.1.0]butane and Cyclobutene
Vladimir Ya. Lee; Shogo Miyazaki; Hiroyuki Yasuda; Akira Sekiguchi; Journal of the American Chemical Society 130 (2008) 2758–2759; doi:10.1021/ja800111r

data_4107497
_publ_section_title
;
 Isomeric Metamorphosis: Si3E (E = S, Se, and Te) Bicyclo[1.1.0]butane and
 Cyclobutene
;
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              2758
_journal_page_last               2759
_journal_paper_doi               10.1021/ja800111r
_journal_volume                  130
_journal_year                    2008
_chemical_formula_sum            'C36 H84 Se Si7'
_chemical_formula_weight         792.62
_chemical_name_systematic
; 
Si3Se-bicyclo[1.1.0]butane 
;
_space_group_IT_number           19
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'P 2ac 2ab'
_symmetry_space_group_name_H-M   'P 21 21 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                   12.6710(4)
_cell_length_b                   17.3960(3)
_cell_length_c                   21.8670(7)
_cell_measurement_reflns_used    48570
_cell_measurement_temperature    150
_cell_measurement_theta_max      27.93
_cell_measurement_theta_min      2.20
_cell_volume                     4820.0(2)
_computing_cell_refinement       'HKL scalepack'
_computing_data_collection       'MacScience Xpress'
_computing_data_reduction        Denzo
_computing_molecular_graphics    ORTEP
_computing_publication_material  CIFTAB
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    SIR92
_diffrn_ambient_temperature      150
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.998
_diffrn_measurement_device_type  'MacScience DIP2030 Image plate'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'rotating anode'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71070
_diffrn_reflns_av_R_equivalents  0.079
_diffrn_reflns_av_sigmaI/netI    0.0399
_diffrn_reflns_limit_h_max       16
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       22
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       28
_diffrn_reflns_limit_l_min       0
_diffrn_reflns_number            48570
_diffrn_reflns_theta_full        27.93
_diffrn_reflns_theta_max         27.93
_diffrn_reflns_theta_min         2.20
_exptl_absorpt_coefficient_mu    0.975
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            yellow
_exptl_crystal_density_diffrn    1.092
_exptl_crystal_description       blocks
_exptl_crystal_F_000             1728
_exptl_crystal_size_max          0.40
_exptl_crystal_size_mid          0.35
_exptl_crystal_size_min          0.30
_refine_diff_density_max         0.760
_refine_diff_density_min         -1.304
_refine_diff_density_rms         0.092
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.531(12)
_refine_ls_extinction_coef       0.0159(12)
_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   1.046
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     398
_refine_ls_number_reflns         6358
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.046
_refine_ls_R_factor_all          0.0630
_refine_ls_R_factor_gt           0.0533
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0998P)^2^+2.1989P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1436
_refine_ls_wR_factor_ref         0.1500
_reflns_number_gt                5456
_reflns_number_total             6358
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ja800111r-file002.cif
_cod_data_source_block           shelxl
_cod_original_sg_symbol_H-M      'P 21 21 21 '
_cod_database_code               4107497