Dimethylcalcium.
Wolf, Benjamin M.; Stuhl, Christoph; Maichle-Mössmer, Cäcilia; Anwander, Reiner; Journal of the American Chemical Society 140 (2018) 2373–2383; doi:10.1021/jacs.7b12984

data_4131920
_publ_section_title
;
 Dimethylcalcium.
;
_journal_issue                   6
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              2373
_journal_page_last               2383
_journal_paper_doi               10.1021/jacs.7b12984
_journal_volume                  140
_journal_year                    2018
_chemical_absolute_configuration unk
_chemical_formula_sum            'C8 H24 Ca Ga2'
_chemical_formula_weight         299.79
_space_group_crystal_system      orthorhombic
_space_group_IT_number           36
_space_group_name_Hall           'C 2c -2'
_space_group_name_H-M_alt        'C m c 21'
_atom_sites_solution_hydrogens   difmap
_audit_creation_method           SHELXL-2014/7
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   7.388(6)
_cell_length_b                   19.802(12)
_cell_length_c                   9.630(5)
_cell_measurement_reflns_used    7767
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      28.54
_cell_measurement_theta_min      2.943
_cell_volume                     1408.8(16)
_computing_cell_refinement       'SAINT V8.37A (Bruker AXS Inc., 2015)'
_computing_data_collection       'Bruker Apex3'
_computing_data_reduction        'SAINT V8.37A (Bruker AXS Inc., 2015)'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-2014/7 (Sheldrick, 2014)'
_computing_structure_solution    'XT, VERSION 2014/5'
_diffrn_ambient_temperature      100(2)
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device_type  'Smart Apex III Duo'
_diffrn_measurement_method       phi-scans
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0586
_diffrn_reflns_av_unetI/netI     0.0289
_diffrn_reflns_Laue_measured_fraction_full 1.000
_diffrn_reflns_Laue_measured_fraction_max 1.000
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       26
_diffrn_reflns_limit_k_min       -26
_diffrn_reflns_limit_l_max       13
_diffrn_reflns_limit_l_min       -13
_diffrn_reflns_number            19037
_diffrn_reflns_point_group_measured_fraction_full 1.000
_diffrn_reflns_point_group_measured_fraction_max 1.000
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         28.704
_diffrn_reflns_theta_min         2.057
_diffrn_source                   Imus-tube
_exptl_absorpt_coefficient_mu    4.145
_exptl_absorpt_correction_T_max  0.7458
_exptl_absorpt_correction_T_min  0.6446
_exptl_absorpt_correction_type   numerical
_exptl_absorpt_process_details   sadabs
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.413
_exptl_crystal_description       plate
_exptl_crystal_F_000             616
_exptl_crystal_size_max          0.111
_exptl_crystal_size_mid          0.083
_exptl_crystal_size_min          0.052
_refine_diff_density_max         0.383
_refine_diff_density_min         -0.228
_refine_diff_density_rms         0.056
_refine_ls_abs_structure_details
;
 Refined as an inversion twin.
;
_refine_ls_abs_structure_Flack   0.343(18)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.017
_refine_ls_hydrogen_treatment    refxyz
_refine_ls_matrix_type           full
_refine_ls_number_parameters     100
_refine_ls_number_reflns         1952
_refine_ls_number_restraints     5
_refine_ls_restrained_S_all      1.017
_refine_ls_R_factor_all          0.0189
_refine_ls_R_factor_gt           0.0172
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0145P)^2^+0.4251P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0377
_refine_ls_wR_factor_ref         0.0384
_reflns_Friedel_coverage         0.890
_reflns_Friedel_fraction_full    1.000
_reflns_Friedel_fraction_max     1.000
_reflns_number_gt                1881
_reflns_number_total             1952
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            ja7b12984_si_002.cif
_cod_data_source_block           8_mo_BW335b_GaMe3_0m
_cod_database_code               4131920
_shelx_shelxl_version_number     2014/7
_shelx_estimated_absorpt_t_min   0.656
_shelx_estimated_absorpt_t_max   0.813
_shelx_res_checksum              32180
_shelx_hkl_checksum              52191