Cr~3~Si~2~O~7~.1/4MX (MX = NaCl, NaBr, KCl, KBr): A Cage Structure Built from [Cr^II^O~4~] and [Si~2~O~7~] Units 1
Anita Schmidt; Robert Glaum; Inorganic Chemistry 36 (1997) 4883–4887; doi:10.1021/ic9700718

data_4323621
_publ_contact_author
;     
                Robert Glaum     
                Institut f\"ur Anorganische und Analytische Chemie     
                Justus-Liebig-Universit\"at Gie\&sen     
                Heinrich-Buff-Ring 58     
                D-35392 Gie\&sen     
                Germany     
;
_publ_contact_author_email       Robert.Glaum@anorg.chemie.uni-giessen.de
_publ_contact_author_fax         '+49 641 7025673'
_publ_contact_author_phone       '+49 641 7025690'
_publ_section_title
;
 Cr~3~Si~2~O~7~.1/4MX (MX = NaCl, NaBr, KCl, KBr): A Cage Structure Built
 from [Cr^II^O~4~] and [Si~2~O~7~] Units 1
;
_journal_name_full               'Inorganic Chemistry'
_journal_page_first              4883
_journal_page_last               4887
_journal_paper_doi               10.1021/ic9700718
_journal_volume                  36
_journal_year                    1997
_chemical_compound_source
;
purple crystals were prepared by reacting mixtures of Cr~2~O~3~, Cr, 
SiO~2~ and the respective alkali halide in evacuated silica ampoules at 
approximately 1350 \%C for two days.
;
_chemical_formula_moiety         NaCr~12~(Si~2~O~7~)~4~Br
_chemical_formula_structural     'Cr~3~Si~2~O~7~* 1/4 NaBr'
_chemical_formula_sum            'Br2 Cr24 Na2 O56 Si16'
_chemical_formula_weight         2799.24
_chemical_name_systematic
; 
dodeca-Chromium(II)-sodiumbromidetetradisilicate 
;
_space_group_IT_number           139
_symmetry_cell_setting           tetragonal
_symmetry_space_group_name_Hall  '-I 4 2'
_symmetry_space_group_name_H-M   'I 4/m m m'
_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            1
_cell_length_a                   10.2596(7)
_cell_length_b                   10.2596(7)
_cell_length_c                   12.969(3)
_cell_measurement_reflns_used    88
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      12.4
_cell_measurement_theta_min      10.5
_cell_volume                     1365.1(3)
_computing_cell_refinement       'STADI4 (STOE & Cie)'
_computing_data_collection
; 
Data collection by the peak/background method, refinement of the cell  
parameters and the reduction of the data were performed using the software  
package STADI4 (STOE & Cie). Scattering factors, dispersion 
corrections and absorption coefficients were taken from International Tables 
for Crystallography, Vol. C. (1992), tables 6.1.1.4, 4.2.6.8 and 4.2.4.2  
respectively. 
;
_computing_data_reduction        'STADI4 (STOE & Cie)'
_computing_publication_material  SHELXL-93
_computing_structure_refinement  'SHELXL-93 (Sheldrick, 1993)'
_computing_structure_solution    'SHELXS-86 (Sheldrick, 1990)'
_diffrn_ambient_temperature      293(2)
_diffrn_measurement_device       'Four circle diffractometer AED2 (Fa. Stoe)'
_diffrn_measurement_method       \q/2\q
_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  0.0254
_diffrn_reflns_av_sigmaI/netI    0.0083
_diffrn_reflns_limit_h_max       14
_diffrn_reflns_limit_h_min       -14
_diffrn_reflns_limit_k_max       14
_diffrn_reflns_limit_k_min       -14
_diffrn_reflns_limit_l_max       18
_diffrn_reflns_limit_l_min       -18
_diffrn_reflns_number            7992
_diffrn_reflns_theta_max         30.03
_diffrn_reflns_theta_min         2.53
_diffrn_standards_decay_%        0.0
_diffrn_standards_interval_time  300
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    6.518
_exptl_absorpt_correction_T_max  0.4128
_exptl_absorpt_correction_T_min  0.2368
_exptl_absorpt_correction_type   'Psi scan (North, Phillips & Mathews, 1968)'
_exptl_crystal_colour            purple
_exptl_crystal_density_diffrn    3.407
_exptl_crystal_description       'square plate'
_exptl_crystal_F_000             1340
_exptl_crystal_size_max          0.17
_exptl_crystal_size_mid          0.14
_exptl_crystal_size_min          0.07
_refine_diff_density_max         0.527
_refine_diff_density_min         -0.550
_refine_diff_density_rms         0.107
_refine_ls_extinction_coef       0.0047(3)
_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   1.427
_refine_ls_goodness_of_fit_obs   1.427
_refine_ls_matrix_type           full
_refine_ls_number_parameters     43
_refine_ls_number_reflns         617
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.427
_refine_ls_restrained_S_obs      1.427
_refine_ls_R_factor_all          0.0247
_refine_ls_R_factor_obs          0.0247
_refine_ls_shift/esd_max         -0.001
_refine_ls_shift/esd_mean        0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0132P)^2^+6.8224P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_all         0.0551
_refine_ls_wR_factor_obs         0.0551
_reflns_number_observed          617
_reflns_number_total             617
_reflns_observed_criterion       >2sigma(I)
_cod_data_source_file            ic9700718_3.cif
_cod_data_source_block           nabr
_cod_depositor_comments
;
The following automatic conversions were performed:

'_geom_bond_publ_flag' value 'Y' changed to 'y' according to the
built-in table from CIF Core dictionary named 'cif_core.dic' version
2.4.1 from 2010-06-29 (33 times).

'_geom_angle_publ_flag' value 'Y'
changed to 'y' according to the built-in table from CIF Core
dictionary named 'cif_core.dic' version 2.4.1 from 2010-06-29 (108
times).

Automatic conversion script
Id: cif_fix_values 1715 2011-07-08 13:25:40Z adriana 

The following automatic conversions were performed:

'_refine_ls_weighting_scheme' value 'calc
w=1/[\s^2^(Fo^2^)+(0.0132P)^2^+6.8224P] 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^)+(0.0132P)^2^+6.8224P] where P=(Fo^2^+2Fc^2^)/3'.

Automatic conversion script
Id: cif_fix_values 3143 2015-03-26 13:38:13Z robertas 
;
_cod_original_cell_volume        1364.4(3)
_cod_database_code               4323621