Polymorphism in phenobarbital: discovery of a new polymorph and crystal structure of elusive form V.
Roy, Saikat; Goud, N. Rajesh; Matzger, Adam J.; Chemical communications (Cambridge, England) 52 (2016) 4389–4392; doi:10.1039/c6cc00959j

data_7118806
_publ_section_title
;
 Polymorphism in phenobarbital: discovery of a new polymorph and crystal
 structure of elusive form V.
;
_journal_issue                   23
_journal_name_full               'Chemical communications (Cambridge, England)'
_journal_page_first              4389
_journal_page_last               4392
_journal_paper_doi               10.1039/c6cc00959j
_journal_volume                  52
_journal_year                    2016
_chemical_formula_moiety         'C12 H12 N2 O3'
_chemical_formula_sum            'C12 H12 N2 O3'
_chemical_formula_weight         232.24
_chemical_name_common            Phenobarbital
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2yn'
_symmetry_space_group_name_H-M   'P 1 21/n 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_audit_update_record
;
2016-01-28 deposited with the CCDC.
2016-02-25 downloaded from the CCDC.
;
_cell_angle_alpha                90.00
_cell_angle_beta                 93.987(7)
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   14.5744(4)
_cell_length_b                   6.88000(19)
_cell_length_c                   22.9964(16)
_cell_measurement_reflns_used    5246
_cell_measurement_temperature    95(2)
_cell_measurement_theta_max      54.2
_cell_measurement_theta_min      6.7
_cell_volume                     2300.31(18)
_computing_data_reduction        'Crystal Structure 3.8'
_computing_publication_material  'Crystal Structure 3.8'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      95(2)
_diffrn_measured_fraction_theta_full 0.986
_diffrn_measured_fraction_theta_max 0.986
_diffrn_measurement_device_type  'rigaku RAXIS conversion'
_diffrn_measurement_method       'profile data from \w-scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54187
_diffrn_reflns_av_R_equivalents  0.0000
_diffrn_reflns_av_sigmaI/netI    0.1185
_diffrn_reflns_limit_h_max       15
_diffrn_reflns_limit_h_min       -15
_diffrn_reflns_limit_k_max       6
_diffrn_reflns_limit_k_min       -7
_diffrn_reflns_limit_l_max       13
_diffrn_reflns_limit_l_min       -24
_diffrn_reflns_number            9546
_diffrn_reflns_theta_full        54.24
_diffrn_reflns_theta_max         54.24
_diffrn_reflns_theta_min         6.72
_exptl_absorpt_coefficient_mu    0.815
_exptl_absorpt_correction_T_max  0.9839
_exptl_absorpt_correction_T_min  0.9439
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
; 
 T. Higashi, (1995). Program for Absorption Correction.
 Rigaku Corporation, Tokyo, Japan.
;
_exptl_crystal_colour            Colorless
_exptl_crystal_density_diffrn    1.341
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       Plate
_exptl_crystal_F_000             976
_exptl_crystal_recrystallization_method 'From the Melt'
_exptl_crystal_size_max          0.12
_exptl_crystal_size_mid          0.06
_exptl_crystal_size_min          0.02
_refine_diff_density_max         0.587
_refine_diff_density_min         -0.590
_refine_diff_density_rms         0.143
_refine_ls_extinction_coef       0.00145(15)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.171
_refine_ls_hydrogen_treatment    riding
_refine_ls_matrix_type           full
_refine_ls_number_parameters     310
_refine_ls_number_reflns         2768
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.171
_refine_ls_R_factor_all          0.1831
_refine_ls_R_factor_gt           0.0818
_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^)+(0.0003P)^2^+16.1750P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1570
_refine_ls_wR_factor_ref         0.2328
_reflns_number_gt                1260
_reflns_number_total             2768
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c6cc00959j2.cif
_cod_data_source_block           PB_form_XV
_cod_depositor_comments
;
The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Monoclinic' changed to 'monoclinic'
according to
/usr/data/users/saulius/crontab/automatic-downloads/rss-feeds/RSC/lib/dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.2 from 2011-04-26.

Automatic conversion script
Id: cif_fix_values 4268 2015-11-12 08:31:59Z antanas 

 Adding full bibliography for 7118805--7118806.cif.
;
_cod_original_sg_symbol_H-M      P21/n
_cod_database_code               7118806