α,α-Difluoro-β-lactone and its Non-Fluorinated Analog
Abboud, Khalil A.; Ocampo, Rogelio; Dolbier Jr, William R.; Acta Crystallographica Section C 53 (1997) 1923–1926; doi:10.1107/S0108270197010020

data_2006781
_publ_section_title
;
 \a,\a-Difluoro-\b-lactone and its Non-Fluorinated Analog
;
_journal_issue                   12
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              1923
_journal_page_last               1926
_journal_paper_doi               10.1107/S0108270197010020
_journal_volume                  53
_journal_year                    1997
_chemical_formula_moiety         'C17 H14 F2 O2'
_chemical_formula_sum            'C17 H14 F2 O2'
_chemical_formula_weight         288.28
_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'
_audit_creation_method           SHELXTL5
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   6.1540(10)
_cell_length_b                   13.484(2)
_cell_length_c                   17.732(3)
_cell_measurement_reflns_used    32
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      11
_cell_measurement_theta_min      10
_cell_volume                     1471.4(4)
_computing_cell_refinement       'P3/PC Diffractometer Program'
_computing_data_collection       'P3/PC Diffractometer Program (Siemens, 1989)'
_computing_data_reduction        'SHELXTL-Plus (Sheldrick, 1990)'
_computing_molecular_graphics    SHELXTL5
_computing_publication_material  SHELXTL5
_computing_structure_refinement  SHELXTL5
_computing_structure_solution    SHELXTL5
_diffrn_ambient_temperature      293(2)
_diffrn_measurement_device       'Siemens P3/PC'
_diffrn_measurement_method       \w
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'normal-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.021
_diffrn_reflns_av_sigmaI/netI    0.040
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_k_max       17
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       23
_diffrn_reflns_limit_l_min       0
_diffrn_reflns_number            4168
_diffrn_reflns_theta_max         27.50
_diffrn_reflns_theta_min         1.90
_diffrn_standards_decay_%        3
_diffrn_standards_interval_count 100
_diffrn_standards_number         4
_exptl_absorpt_coefficient_mu    0.10
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            Colorless
_exptl_crystal_density_diffrn    1.301
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       Needle
_exptl_crystal_F_000             600
_exptl_crystal_size_max          0.47
_exptl_crystal_size_mid          0.27
_exptl_crystal_size_min          0.23
_refine_diff_density_max         0.09
_refine_diff_density_min         -0.08
_refine_ls_extinction_coef       0.035(2)
_refine_ls_extinction_method     SHELXTL5
_refine_ls_goodness_of_fit_all   1.05
_refine_ls_goodness_of_fit_obs   1.24
_refine_ls_hydrogen_treatment    'H atoms riding'
_refine_ls_matrix_type           full
_refine_ls_number_parameters     191
_refine_ls_number_reflns         3052
_refine_ls_number_restraints     0
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_refine_ls_restrained_S_obs      1.24
_refine_ls_R_factor_all          0.072
_refine_ls_R_factor_obs          .034
_refine_ls_shift/esd_max         -0.02
_refine_ls_shift/esd_mean        0.002
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w = 1/[\s^2^(Fo^2^)+(0.0245P)^2^] where P = (Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_all         0.070
_refine_ls_wR_factor_obs         .060
_reflns_number_observed          1816
_reflns_number_total             3055
_reflns_observed_criterion       >2sigma(I)
_cod_data_source_file            bs1033.cif
_cod_data_source_block           2
_cod_depositor_comments
;
The following automatic conversions were performed:
'_symmetry_cell_setting' value 'Orthorhombic' changed to 'orthorhombic'
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 'Orthorhombic' changed to
'orthorhombic' 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^)+(0.0245P)^2^] 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^)+(0.0245P)^2^]
where P = (Fo^2^+2Fc^2^)/3'.

Automatic conversion script
Id: cif_fix_values 3143 2015-03-26 13:38:13Z robertas 
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_cod_database_code               2006781