A Remarkable Isostructural Homologous Series of Mixed Lithium-Heavier Alkali Metaltert-Butoxides [(t-BuO)8Li4M4] (M = Na, K, Rb or Cs)
David R. Armstrong; William Clegg; Allison M. Drummond; Stephen T. Liddle; Robert E. Mulvey; Journal of the American Chemical Society 122 (2000) 11117–11124; doi:10.1021/ja002217z

data_4116232
_publ_section_title
;
 A Remarkable Isostructural Homologous Series of Mixed Lithium-Heavier
 Alkali Metaltert-Butoxides [(t-BuO)8Li4M4] (M = Na, K, Rb or Cs)
;
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              11117
_journal_page_last               11124
_journal_paper_doi               10.1021/ja002217z
_journal_volume                  122
_journal_year                    2000
_chemical_formula_sum            'C32 H72 Li4 Na4 O8'
_chemical_formula_weight         704.62
_space_group_IT_number           4
_symmetry_cell_setting           monoclinic
_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_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 102.899(9)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   18.998(3)
_cell_length_b                   12.010(3)
_cell_length_c                   20.402(3)
_cell_measurement_reflns_used    13239
_cell_measurement_temperature    160(2)
_cell_measurement_theta_max      27.01
_cell_measurement_theta_min      2.62
_cell_volume                     4537.6(15)
_computing_cell_refinement       'local programs'
_computing_data_collection       'Siemens SMART'
_computing_data_reduction        'Siemens SAINT'
_computing_molecular_graphics    'Siemens SHELXTL'
_computing_publication_material  'SHELXTL and local programs'
_computing_structure_refinement  'Siemens SHELXTL'
_computing_structure_solution    'Siemens SHELXTL'
_diffrn_ambient_temperature      160(2)
_diffrn_measured_fraction_theta_full 0.997
_diffrn_measured_fraction_theta_max 0.997
_diffrn_measurement_device_type  'Siemens SMART CCD diffractometer'
_diffrn_measurement_method       '\w rotation with narrow frames'
_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  0.0216
_diffrn_reflns_av_sigmaI/netI    0.0474
_diffrn_reflns_limit_h_max       22
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -14
_diffrn_reflns_limit_l_max       24
_diffrn_reflns_limit_l_min       -24
_diffrn_reflns_number            22836
_diffrn_reflns_theta_full        25.00
_diffrn_reflns_theta_max         25.00
_diffrn_reflns_theta_min         1.98
_diffrn_standards_decay_%        0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.101
_exptl_absorpt_correction_T_max  0.9279
_exptl_absorpt_correction_T_min  0.8040
_exptl_absorpt_correction_type   empirical
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.031
_exptl_crystal_description       block
_exptl_crystal_F_000             1536
_exptl_crystal_size_max          0.82
_exptl_crystal_size_mid          0.80
_exptl_crystal_size_min          0.74
_refine_diff_density_max         0.170
_refine_diff_density_min         -0.219
_refine_diff_density_rms         0.031
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.64(16)
_refine_ls_extinction_coef       0.00096(17)
_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   0.976
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     914
_refine_ls_number_reflns         15089
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      0.976
_refine_ls_R_factor_all          0.0585
_refine_ls_R_factor_gt           0.0376
_refine_ls_shift/su_max          0.003
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0452P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0799
_refine_ls_wR_factor_ref         0.0871
_reflns_number_gt                11564
_reflns_number_total             15089
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ja002217z_2.cif
_cod_data_source_block           rem259
_cod_original_cell_volume        4537.5(13)
_cod_database_code               4116232