The selective dissolution of rice hull ash to form [OSiO1.5]8[R4N]8(R = Me, CH2CH2OH) octasilicates. Basic nanobuilding blocks and possible models of intermediates formed during biosilicification processes
Asuncion, M. Z.; Hasegawa, I.; Kampf, J. W.; Laine, R. M.; Journal of Materials Chemistry 15 (2005) 2114–; doi:10.1039/b502178b

data_7203748
_publ_section_title
;
 The selective dissolution of rice hull ash to form [OSiO1.5]8[R4N]8(R
 = Me, CH2CH2OH) octasilicates. Basic nanobuilding blocks and possible
 models of intermediates formed during biosilicification processes
;
_journal_issue                   21
_journal_name_full               'Journal of Materials Chemistry'
_journal_page_first              2114
_journal_paper_doi               10.1039/b502178b
_journal_volume                  15
_journal_year                    2005
_chemical_formula_sum            'C40 H160 N8 O52 Si8'
_chemical_formula_weight         1810.48
_chemical_name_systematic
;
?
;
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2yn'
_symmetry_space_group_name_H-M   'P 1 21/n 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                 90.8860(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            2
_cell_length_a                   11.9649(9)
_cell_length_b                   16.5185(12)
_cell_length_c                   20.8305(16)
_cell_measurement_reflns_used    5542
_cell_measurement_temperature    158(2)
_cell_measurement_theta_max      25.94
_cell_measurement_theta_min      2.33
_cell_volume                     4116.5(5)
_computing_cell_refinement       'Bruker SMART'
_computing_data_collection       'Bruker SMART'
_computing_data_reduction        'Bruker SHELXTL'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'Bruker SHELXTL'
_computing_structure_solution    'Bruker SHELXTL'
_diffrn_ambient_temperature      158(2)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'CCD area detector'
_diffrn_measurement_method       'phi and omega scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0440
_diffrn_reflns_av_sigmaI/netI    0.0458
_diffrn_reflns_limit_h_max       14
_diffrn_reflns_limit_h_min       -14
_diffrn_reflns_limit_k_max       20
_diffrn_reflns_limit_k_min       -20
_diffrn_reflns_limit_l_max       26
_diffrn_reflns_limit_l_min       -26
_diffrn_reflns_number            40536
_diffrn_reflns_theta_full        26.40
_diffrn_reflns_theta_max         26.40
_diffrn_reflns_theta_min         1.57
_exptl_absorpt_coefficient_mu    0.237
_exptl_absorpt_correction_T_max  0.978
_exptl_absorpt_correction_T_min  0.871
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'Blessing, Acta Cryst. (1995) A51 33-38.'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.461
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             1968
_exptl_crystal_size_max          0.20
_exptl_crystal_size_mid          0.22
_exptl_crystal_size_min          0.26
_refine_diff_density_max         0.802
_refine_diff_density_min         -0.769
_refine_diff_density_rms         0.099
_refine_ls_extinction_coef       0.0006(8)
_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   1.095
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     522
_refine_ls_number_reflns         8427
_refine_ls_number_restraints     3
_refine_ls_restrained_S_all      1.151
_refine_ls_R_factor_all          0.0973
_refine_ls_R_factor_gt           0.0676
_refine_ls_shift/su_max          0.005
_refine_ls_shift/su_mean         0.001
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.1487P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.2122
_refine_ls_wR_factor_ref         0.2294
_reflns_number_gt                5610
_reflns_number_total             8427
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            b502178b.txt
_cod_data_source_block           cholsi
_cod_depositor_comments
;
The following automatic conversions were performed:
'_symmetry_cell_setting' value 'Monoclinic' changed to 'monoclinic'
according to '/home/saulius/struct/CIF-dictionaries/cif_core.dic'
dictionary named 'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_enum 1527 2010-12-29 10:47:43Z saulius 
;
_cod_original_sg_symbol_H-M      P2(1)/n
_cod_database_code               7203748