Two polymorphs of 20-desmethyl-β-carotene
Helliwell, Madeleine; Liaaen-Jensen, Synnøve; Wilkinson, James; Acta Crystallographica Section C 64 (2008) o252–o256; doi:10.1107/S0108270108007816

data_2016602
_publ_section_title
;
 Two polymorphs of 20-desmethyl-\b-carotene
;
_journal_coeditor_code           JZ3128
_journal_issue                   5
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              o252
_journal_page_last               o256
_journal_paper_doi               10.1107/S0108270108007816
_journal_volume                  64
_journal_year                    2008
_chemical_formula_iupac          'C39 H54'
_chemical_formula_moiety         'C39 H54'
_chemical_formula_sum            'C39 H54'
_chemical_formula_weight         522.82
_chemical_name_common            20-Desmethyl-\b-carotene
_chemical_name_systematic
;
20-nor-\b,\b-carotene
;
_space_group_IT_number           4
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  'P 2yb'
_symmetry_space_group_name_H-M   'P 1 21 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL97
_cell_angle_alpha                90.00
_cell_angle_beta                 93.733(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            2
_cell_length_a                   9.442(2)
_cell_length_b                   7.6914(16)
_cell_length_c                   23.090(5)
_cell_measurement_reflns_used    879
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      23.42
_cell_measurement_theta_min      2.16
_cell_volume                     1673.3(6)
_computing_cell_refinement       'SMART (Bruker, 2001)'
_computing_data_collection       'SMART (Bruker, 2001)'
_computing_data_reduction        'SMART (Bruker, 2001)'
_computing_molecular_graphics    'SHELXTL (Bruker, 2001)'
_computing_publication_material  'SHELXTL (Bruker, 2001)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      100(2)
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.998
_diffrn_measurement_device_type  'Bruker SMART CCD area-detector'
_diffrn_measurement_method       '\f and \w'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0850
_diffrn_reflns_av_sigmaI/netI    0.1537
_diffrn_reflns_limit_h_max       11
_diffrn_reflns_limit_h_min       -11
_diffrn_reflns_limit_k_max       6
_diffrn_reflns_limit_k_min       -9
_diffrn_reflns_limit_l_max       24
_diffrn_reflns_limit_l_min       -27
_diffrn_reflns_number            8554
_diffrn_reflns_theta_full        25.03
_diffrn_reflns_theta_max         25.03
_diffrn_reflns_theta_min         1.77
_exptl_absorpt_coefficient_mu    0.058
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            orange
_exptl_crystal_density_diffrn    1.038
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             576
_exptl_crystal_size_max          0.40
_exptl_crystal_size_mid          0.22
_exptl_crystal_size_min          0.05
_refine_diff_density_max         0.149
_refine_diff_density_min         -0.153
_refine_ls_extinction_coef       0.0090(11)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     'SHELXL97 (Sheldrick, 2008)'
_refine_ls_goodness_of_fit_ref   0.853
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     373
_refine_ls_number_reflns         3195
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      0.853
_refine_ls_R_factor_all          0.1359
_refine_ls_R_factor_gt           0.0579
_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^)+(0.0379P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0964
_refine_ls_wR_factor_ref         0.1115
_reflns_number_gt                1530
_reflns_number_total             3196
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            jz3128.cif
_cod_data_source_block           I-P21
_cod_original_sg_symbol_Hall     P2yb
_cod_original_sg_symbol_H-M      P21
_cod_database_code               2016602
_cod_database_fobs_code          2016602