Two Cyclotetrasiloxanes at 143K
Hensen, Karl; Gebhardt, Frank; Kettner, Markus; Pickel, Peter; Bolte, Michael; Acta Crystallographica Section C 53 (1997) 1867–1869; doi:10.1107/S0108270197010068

data_2006838
_publ_section_title
;
 Two Cyclotetrasiloxanes at 143K
;
_journal_issue                   12
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              1867
_journal_page_last               1869
_journal_paper_doi               10.1107/S0108270197010068
_journal_volume                  53
_journal_year                    1997
_chemical_formula_sum            'C16 H32 O4 Si4'
_chemical_formula_weight         400.78
_chemical_name_systematic
;
1,3,5,7-Tetra(cyclotetramethylen)cyclotetrasiloxane
;
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/c 1'
_audit_creation_method           SHELXL
_cell_angle_alpha                90
_cell_angle_beta                 99.0360(10)
_cell_angle_gamma                90
_cell_formula_units_Z            2
_cell_length_a                   6.36030(10)
_cell_length_b                   17.8106(3)
_cell_length_c                   9.33630(10)
_cell_measurement_reflns_used    4336
_cell_measurement_temperature    143
_cell_measurement_theta_max      25.00
_cell_measurement_theta_min      1.00
_cell_volume                     1044.50(3)
_computing_cell_refinement       SMART
_computing_data_collection       'SMART (Siemens, 1995)'
_computing_data_reduction        'SAINT (Siemens, 1995)'
_computing_molecular_graphics    'XP in SHELXTL-Plus (Sheldrick, 1991)'
_computing_structure_refinement  'SHELXL96 (Sheldrick, 1996b)'
_computing_structure_solution    'SHELXS96 (Sheldrick, 1990)'
_diffrn_ambient_temperature      143
_diffrn_measured_fraction_theta_full 0.958
_diffrn_measured_fraction_theta_max 0.958
_diffrn_measurement_device       'Siemens CCD three-circle diffractometer'
_diffrn_measurement_method       \w
_diffrn_radiation_monochromator  'highly oriented graphite crystal'
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0820
_diffrn_reflns_av_sigmaI/netI    0.0551
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_k_max       21
_diffrn_reflns_limit_k_min       -19
_diffrn_reflns_limit_l_max       11
_diffrn_reflns_limit_l_min       -11
_diffrn_reflns_number            13687
_diffrn_reflns_theta_full        26.43
_diffrn_reflns_theta_max         26.43
_diffrn_reflns_theta_min         2.49
_diffrn_standards_decay_%        0
_diffrn_standards_interval_time  600
_diffrn_standards_number         130
_exptl_absorpt_coefficient_mu    0.301
_exptl_absorpt_correction_T_max  1.000
_exptl_absorpt_correction_T_min  0.874
_exptl_absorpt_correction_type   'Empirical (SADABS; Sheldrick, 1996a)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.274
_exptl_crystal_description       plate
_exptl_crystal_F_000             432
_exptl_crystal_size_max          0.40
_exptl_crystal_size_mid          0.20
_exptl_crystal_size_min          0.05
_refine_diff_density_max         0.460
_refine_diff_density_min         -0.394
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.048
_refine_ls_hydrogen_treatment    'H atoms: see text'
_refine_ls_matrix_type           full
_refine_ls_number_parameters     108
_refine_ls_number_reflns         2122
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.048
_refine_ls_R_factor_all          0.0891
_refine_ls_R_factor_gt           0.0546
_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^)+(0.0438P)^2^+1.5197P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_ref         0.1227
_reflns_number_observed          1531
_reflns_number_total             2122
_reflns_observed_criterion       >2sigma(I)
_cod_data_source_file            jz1227.cif
_cod_data_source_block           II
_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 

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_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^)+(0.0438P)^2^+1.5197P] 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^)+(0.0438P)^2^+1.5197P] 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      'P 21/c'
_cod_database_code               2006838