Precursors to dodecahedrane
Lakshminarasimhan Damodharan; Vasantha Pattabhi; Rallapalli Sivakumar; Sambasivarao Kotha; Acta Crystallographica Section C 59 (2003) o373–o375; doi:10.1107/S0108270103010825

data_2013486
_publ_section_title
;
 Precursors to dodecahedrane
;
_journal_issue                   7
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              o373
_journal_page_last               o375
_journal_paper_doi               10.1107/S0108270103010825
_journal_volume                  59
_journal_year                    2003
_chemical_formula_iupac          'C20 H26 O4'
_chemical_formula_moiety         'C20 H26 O4'
_chemical_formula_sum            'C20 H26 O4'
_chemical_formula_weight         330.41
_chemical_name_systematic
;
(2R,2''S,3'bS,4'aR,7'bS,8'aR)-perhydrodispiro[furan-2,3'-
dicyclopenta[a,e]pentalene-7',2''-furan]-5,5''-dione
;
_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'
_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                 91.54(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   7.085(3)
_cell_length_b                   12.064(5)
_cell_length_c                   19.583(5)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      25.62
_cell_measurement_theta_min      8.64
_cell_volume                     1673.2(11)
_computing_cell_refinement       'CAD-4 EXPRESS'
_computing_data_collection       'CAD-4 EXPRESS (Enraf--Nonius, 1995)'
_computing_data_reduction        'XCAD4 (Harms & Wocadlo, 1995)'
_computing_molecular_graphics
'ORTEP-3 (Johnson & Burnett, 1996; Farrugia, 1999)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'Enraf Nonius CAD4'
_diffrn_measurement_method       'non-profiled \w/2\q scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.5418
_diffrn_reflns_av_R_equivalents  0.0353
_diffrn_reflns_av_sigmaI/netI    0.0642
_diffrn_reflns_limit_h_max       8
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       14
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       23
_diffrn_reflns_limit_l_min       -23
_diffrn_reflns_number            3346
_diffrn_reflns_theta_full        67.98
_diffrn_reflns_theta_max         67.98
_diffrn_reflns_theta_min         4.30
_diffrn_standards_decay_%        0
_diffrn_standards_interval_count 200
_diffrn_standards_interval_time  120
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    0.725
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.312
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       'Rectangular needle'
_exptl_crystal_F_000             712
_exptl_crystal_size_max          0.2
_exptl_crystal_size_mid          0.05
_exptl_crystal_size_min          0.0075
_refine_diff_density_max         0.185
_refine_diff_density_min         -0.259
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.022
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     217
_refine_ls_number_reflns         3054
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.022
_refine_ls_R_factor_all          0.1159
_refine_ls_R_factor_gt           0.0512
_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^)+(0.0676P)^2^+0.0257P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1192
_refine_ls_wR_factor_ref         0.1430
_reflns_number_gt                1727
_reflns_number_total             3054
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            na1610.cif
_cod_data_source_block           I
_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 
;
_cod_original_sg_symbol_H-M      'P 21/c'
_cod_database_code               2013486
_cod_database_fobs_code          2013486