The Unusual Stability of Homoleptic Di- and Tetravalent Chromium Alkyls
Schulzke, Carola; Enright, Dave; Sugiyama, Hiroyasu; LeBlanc, Guy; Gambarotta, Sandro; Yap, Glenn P. A.; Thompson, Laurence K.; Wilson, David R.; Duchateau, Rob; Organometallics 21 (2002) 3810–; doi:10.1021/om020237z

data_4076887
_publ_section_title
;
 The Unusual Stability of Homoleptic Di- and Tetravalent Chromium Alkyls
;
_journal_issue                   18
_journal_name_full               Organometallics
_journal_page_first              3810
_journal_paper_doi               10.1021/om020237z
_journal_volume                  21
_journal_year                    2002
_chemical_formula_sum            'C16 H44 Cr Si4'
_chemical_formula_weight         400.87
_chemical_name_systematic
; 
 ? 
;
_space_group_IT_number           15
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-C 2yc'
_symmetry_space_group_name_H-M   'C 1 2/c 1'
_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                 116.2890(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   18.7133(18)
_cell_length_b                   8.3575(8)
_cell_length_c                   18.7599(18)
_cell_measurement_reflns_used    'reflections from 60 data frames'
_cell_measurement_temperature    203(2)
_cell_measurement_theta_max      28.29
_cell_measurement_theta_min      1.47
_cell_volume                     2630.5(4)
_computing_cell_refinement       'Bruker SMART'
_computing_data_collection       'Bruker SMART'
_computing_data_reduction        'Bruker SHELXTL'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      203(2)
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_method       'phi and omega 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  0.0921
_diffrn_reflns_av_sigmaI/netI    0.1220
_diffrn_reflns_limit_h_max       19
_diffrn_reflns_limit_h_min       -22
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       22
_diffrn_reflns_limit_l_min       0
_diffrn_reflns_number            7547
_diffrn_reflns_theta_full        25.00
_diffrn_reflns_theta_max         25.00
_diffrn_reflns_theta_min         2.42
_diffrn_standards_decay_%        <1
_diffrn_standards_number         '50 standard frames at start and end'
_exptl_absorpt_coefficient_mu    0.613
_exptl_absorpt_correction_T_max  0.928076
_exptl_absorpt_correction_T_min  0.649701
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'Blessing,R., Acta Cryst. (1995) A51 33-38.'
_exptl_crystal_colour            aubergine
_exptl_crystal_density_diffrn    1.012
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             880
_exptl_crystal_size_max          0.18
_exptl_crystal_size_mid          0.15
_exptl_crystal_size_min          0.03
_refine_diff_density_max         0.388
_refine_diff_density_min         -0.412
_refine_diff_density_rms         0.085
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.053
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     168
_refine_ls_number_reflns         2313
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.053
_refine_ls_R_factor_all          0.0972
_refine_ls_R_factor_gt           0.0904
_refine_ls_shift/su_max          0.005
_refine_ls_shift/su_mean         0.001
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0500P)^2^+60.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.2388
_refine_ls_wR_factor_ref         0.2420
_reflns_number_gt                2075
_reflns_number_total             2313
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            om020237z.cif
_cod_data_source_block           sg412
_cod_original_sg_symbol_H-M      C2/c
_cod_database_code               4076887