Synthesis and Characterization of Stable Stoichiometric Clathrates of Silicon and Germanium: Cs8Na16Si136 and Cs8Na16Ge136
Svilen Bobev; Slavi C. Sevov; Journal of the American Chemical Society 121 (1999) 3795–3796; doi:10.1021/ja9844175

data_4116352
_publ_section_title
;
 Synthesis and Characterization of Stable Stoichiometric Clathrates of
 Silicon and Germanium: Cs8Na16Si136 and Cs8Na16Ge136
;
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              3795
_journal_page_last               3796
_journal_paper_doi               10.1021/ja9844175
_journal_volume                  121
_journal_year                    1999
_chemical_compound_source        pure_elements
_chemical_formula_analytical     Cs8_Na16_Si136
_chemical_formula_moiety         Si34
_chemical_formula_structural     Cs8_Na16_Si136
_chemical_formula_sum            'Cs Na2 Si17'
_chemical_formula_weight         656.42
_chemical_name_common            clathrate_II_type
_chemical_name_systematic
;
 ?
;
_space_group_IT_number           227
_symmetry_cell_setting           cubic
_symmetry_space_group_name_Hall  '-F 4vw 2vw 3'
_symmetry_space_group_name_H-M   'F d -3 m :2'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   14.7560(4)
_cell_length_b                   14.7560(4)
_cell_length_c                   14.7560(4)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      39.889
_cell_measurement_theta_min      12.018
_cell_volume                     3212.96(15)
_computing_cell_refinement       CAD4_(Enraf-Nonius,_1977)
_computing_data_collection       CAD4_(Enraf-Nonius,_1977)
_computing_data_reduction        SDP_Package_(Enraf-Nonius,_1985)
_computing_molecular_graphics    'SHELXTL (Siemens, 1994)'
_computing_publication_material  'SHELXTL (Siemens, 1994)'
_computing_structure_refinement  'SHELXL-93 (Sheldrick, 1993)'
_computing_structure_solution    'SHELXS-86 (Sheldrick, 1990)'
_diffrn_ambient_temperature      293(2)
_diffrn_measurement_device       Enraf_Nonius_CAD4
_diffrn_measurement_method       omega-2theta
_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  0.0256
_diffrn_reflns_av_sigmaI/netI    0.0137
_diffrn_reflns_limit_h_max       29
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       29
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       29
_diffrn_reflns_limit_l_min       0
_diffrn_reflns_number            3322
_diffrn_reflns_theta_max         44.90
_diffrn_reflns_theta_min         2.39
_diffrn_standards_interval_count 200
_diffrn_standards_interval_time  120
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    3.606
_exptl_absorpt_correction_T_max  0.000
_exptl_absorpt_correction_T_min  0.000
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            'bluish, metallic luster'
_exptl_crystal_density_diffrn    2.714
_exptl_crystal_description       bar
_exptl_crystal_F_000             2520
_exptl_crystal_size_max          0.2
_exptl_crystal_size_mid          0.2
_exptl_crystal_size_min          0.2
_refine_diff_density_max         0.773
_refine_diff_density_min         -0.508
_refine_diff_density_rms         0.081
_refine_ls_extinction_coef       0.00015(3)
_refine_ls_extinction_expression Fc^*^=3DkFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_all   1.203
_refine_ls_goodness_of_fit_obs   1.235
_refine_ls_matrix_type           full
_refine_ls_number_parameters     15
_refine_ls_number_reflns         680
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.203
_refine_ls_restrained_S_obs      1.235
_refine_ls_R_factor_all          0.0231
_refine_ls_R_factor_obs          0.0201
_refine_ls_shift/esd_max         0.000
_refine_ls_shift/esd_mean        0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0183P)^2^+1.8215P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_all         0.0462
_refine_ls_wR_factor_obs         0.0453
_reflns_number_observed          622
_reflns_number_total             680
_reflns_observed_criterion       >2sigma(I)
_cod_data_source_file            ja9844175_1.cif
_cod_data_source_block           1
_cod_depositor_comments
;
The following automatic conversions were performed:

'_refine_ls_weighting_scheme' value 'calc
w=1/[\s^2^(Fo^2^)+(0.0183P)^2^+1.8215P] where P=(Fo^2^+2Fc^2^)/3' was
changed to 'calc'. New tag '_refine_ls_weighting_details' was
created. The value of the new tag was set to
'w=1/[\s^2^(Fo^2^)+(0.0183P)^2^+1.8215P] where P=(Fo^2^+2Fc^2^)/3'.

Automatic conversion script
Id: cif_fix_values 3143 2015-03-26 13:38:13Z robertas 
;
_cod_original_sg_symbol_H-M      'F d -3 m'
_cod_database_code               4116352