Hydrogen atom behaviour imaged in a short intramolecular hydrogen bond using the combined approach of X-ray and neutron diffraction
Thomas, Lynne H.; Florence, Alastair J.; Wilson, Chick C.; New Journal of Chemistry 33 (2009) 2486–; doi:10.1039/b908915b

data_7053826
_publ_section_title
;
 Hydrogen atom behaviour imaged in a short intramolecular hydrogen bond
 using the combined approach of X-ray and neutron diffraction
;
_journal_issue                   12
_journal_name_full               'New Journal of Chemistry'
_journal_page_first              2486
_journal_paper_doi               10.1039/b908915b
_journal_volume                  33
_journal_year                    2009
_chemical_formula_moiety         'C15 O2 H12'
_chemical_formula_sum            'C15 H12 O2'
_chemical_formula_weight         224.25
_chemical_name_common            dibenzoylmethane
_chemical_name_systematic
;
dibenzoylmethane
;
_space_group_IT_number           61
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  '-P 2ac 2ab'
_symmetry_space_group_name_H-M   'P b c a'
_atom_sites_solution_hydrogens   difmap
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   8.723(3)
_cell_length_b                   10.7969(12)
_cell_length_c                   24.4233(16)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    240(2)
_cell_volume                     2300.2(8)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      240(2)
_diffrn_measurement_device       SXD
_diffrn_measurement_method       'time of flight LAUE diffraction'
_diffrn_radiation_monochromator  none
_diffrn_radiation_probe          neutron
_diffrn_radiation_source         'ISIS spallation source'
_diffrn_radiation_type           neutron
_diffrn_radiation_wavelength     0.5-5.0
_diffrn_reflns_av_R_equivalents  0.0700
_diffrn_reflns_av_sigmaI/netI    0.0570
_diffrn_reflns_limit_h_max       16
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       0
_diffrn_reflns_limit_k_min       -14
_diffrn_reflns_limit_l_max       0
_diffrn_reflns_limit_l_min       -39
_diffrn_reflns_number            2592
_diffrn_reflns_theta_max         14.14
_diffrn_reflns_theta_min         1.74
_exptl_absorpt_coefficient_mu    '1.72, at 1 Angstrom'
_exptl_absorpt_correction_T_max  0.773
_exptl_absorpt_correction_T_min  0.513
_exptl_absorpt_correction_type   empirical
_exptl_absorpt_process_details
;
The linear absorption coefficient is wavelength dependent
and it is calculated as:
mu = 0.89 + 0.83 * lambda [cm^-1]
;
_exptl_crystal_colour            white
_exptl_crystal_density_diffrn    1.294
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             53
_exptl_crystal_size_max          2.5
_exptl_crystal_size_mid          2.0
_exptl_crystal_size_min          1.5
_refine_diff_density_max         0.074
_refine_diff_density_min         -0.069
_refine_diff_density_rms         0.018
_refine_ls_extinction_coef       0.165
_refine_ls_extinction_method     'Becker-Coppens Lorentzian model'
_refine_ls_goodness_of_fit_ref   1.502
_refine_ls_hydrogen_treatment    refall
_refine_ls_matrix_type           full
_refine_ls_number_parameters     262
_refine_ls_number_reflns         836
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.502
_refine_ls_R_factor_all          0.0761
_refine_ls_R_factor_gt           0.0761
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.1000P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1539
_refine_ls_wR_factor_ref         0.1539
_reflns_number_gt                836
_reflns_number_total             836
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            b908915bsup1.cif
_cod_data_source_block           dbm240
_cod_original_sg_symbol_H-M      Pbca
_cod_database_code               7053826