About the Keggin Isomers: Crystal Structure of [N(C4H9)4]4-γ-[SiW12O40], the γ-Isomer of the Keggin Ion. Synthesis and 183W NMR Characterization of the Mixed γ-[SiMo2W10O40]n- (n = 4 or 6)
André Tézé; Emmanuel Cadot; Virginie Béreau; Gilbert Hervé; Inorganic Chemistry 40 (2001) 2000–2004; doi:10.1021/ic000864l

data_4319532
_publ_contact_author
; 
      prof. G. Herve
      institut lavoisier, irem, umr c 0173 
      universit\'e de versailles saint quentin 
      45 avenue des etats unis 
      78035 versailles cedex 
      france 
;
_publ_contact_author_email       herve@chimie.uvsq.fr
_publ_contact_author_fax         '(33) 1 39 25 43 81'
_publ_contact_author_phone       '(33) 1 39 25 43 82'
_publ_section_title
;
 About the Keggin Isomers: Crystal Structure of [N(C4H9)4]4-\g-[SiW12O40],
 the \g-Isomer of the Keggin Ion. Synthesis and 183W NMR Characterization
 of the Mixed \g-[SiMo2W10O40]n- (n = 4 or 6)
;
_journal_name_full               'Inorganic Chemistry'
_journal_page_first              2000
_journal_page_last               2004
_journal_paper_doi               10.1021/ic000864l
_journal_volume                  40
_journal_year                    2001
_chemical_formula_sum            'C64 H144 N4 O40 Si W12'
_chemical_formula_weight         3844.12
_chemical_name_systematic
; 
 ? 
;
_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
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   19.0881(3)
_cell_length_b                   21.4435(3)
_cell_length_c                   26.0799(1)
_cell_measurement_reflns_used    32553
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      29.755
_cell_measurement_theta_min      1.470
_cell_volume                     10674.9(2)
_computing_cell_refinement       'SMART (Siemens 1996)'
_computing_data_collection       'SMART (Siemens 1996)'
_computing_data_reduction        'Siemens SHELXTL(1994)'
_computing_molecular_graphics    'Siemens SHELXTL(1994)'
_computing_publication_material  'Siemens SHELXTL(1994)'
_computing_structure_refinement  'SHELXL-93 (Sheldrick, 1993)'
_computing_structure_solution    'SHELXS-86 (Sheldrick, 1990)'
_diffrn_ambient_temperature      296(2)
_diffrn_measurement_device       'Siemens SMART CCD'
_diffrn_measurement_method       '\w 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  0.1039
_diffrn_reflns_av_sigmaI/netI    0.1468
_diffrn_reflns_limit_h_max       25
_diffrn_reflns_limit_h_min       -22
_diffrn_reflns_limit_k_max       26
_diffrn_reflns_limit_k_min       -28
_diffrn_reflns_limit_l_max       35
_diffrn_reflns_limit_l_min       -35
_diffrn_reflns_number            72164
_diffrn_reflns_theta_max         29.62
_diffrn_reflns_theta_min         1.23
_diffrn_standards_decay_%        0
_diffrn_standards_interval_count 0
_diffrn_standards_interval_time  0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    12.954
_exptl_absorpt_correction_T_max  0.694714
_exptl_absorpt_correction_T_min  0.288086
_exptl_absorpt_correction_type   sadabs
_exptl_absorpt_process_details   'Blessing, Acta Cryst. (1995) A51 33-38'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    2.392
_exptl_crystal_density_meas      ?
_exptl_crystal_description       paralellepiped
_exptl_crystal_F_000             7112
_exptl_crystal_size_max          0.6
_exptl_crystal_size_mid          0.36
_exptl_crystal_size_min          0.30
_refine_diff_density_max         2.403
_refine_diff_density_min         -2.513
_refine_diff_density_rms         0.296
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.03(2)
_refine_ls_extinction_coef       0.000187(11)
_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_all   0.974
_refine_ls_goodness_of_fit_obs   1.033
_refine_ls_matrix_type           full
_refine_ls_number_parameters     744
_refine_ls_number_reflns         26927
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.979
_refine_ls_restrained_S_obs      1.033
_refine_ls_R_factor_all          0.1293
_refine_ls_R_factor_obs          0.0591
_refine_ls_shift/esd_max         -0.016
_refine_ls_shift/esd_mean        0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0586P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_all         0.1449
_refine_ls_wR_factor_obs         0.1162
_reflns_number_observed          15700
_reflns_number_total             26931
_reflns_observed_criterion       >2sigma(I)
_cod_data_source_file            ic000864l.cif
_cod_data_source_block           ortho
_cod_depositor_comments
;
The following automatic conversions were performed:

'_exptl_crystal_density_meas' value 'not measured' was changed to '?'
- the value is perceived as not measured.

Automatic conversion script
Id: cif_fix_values 3008 2015-01-20 13:52:24Z robertas 

The following automatic conversions were performed:

'_refine_ls_weighting_scheme' value 'calc
w=1/[\s^2^(Fo^2^)+(0.0586P)^2^+0.0000P] 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^)+(0.0586P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'.

Automatic conversion script
Id: cif_fix_values 3143 2015-03-26 13:38:13Z robertas 
;
_cod_database_code               4319532