Structural study of piracetam polymorphs and cocrystals: crystallography redetermination and quantum mechanics calculations
Tilborg, Anaëlle; Jacquemin, Denis; Norberg, Bernadette; Perpète, Eric; Michaux, Catherine; Wouters, Johan; Acta Crystallographica Section B 67 (2011) 499–507; doi:10.1107/S0108768111045113

data_2105048
_publ_section_title
;
 Structural study of piracetam polymorphs and cocrystals: crystallography
 redetermination and quantum mechanics calculations
;
_journal_coeditor_code           ZB5018
_journal_issue                   6
_journal_name_full               'Acta Crystallographica Section B'
_journal_page_first              499
_journal_page_last               507
_journal_paper_doi               10.1107/S0108768111045113
_journal_volume                  67
_journal_year                    2011
_chemical_formula_moiety         'C6 H10 N2 O2'
_chemical_formula_sum            'C6 H10 N2 O2'
_chemical_formula_weight         142.16
_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
_cell_angle_alpha                90.00
_cell_angle_beta                 92.087(4)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   6.5030(10)
_cell_length_b                   6.4180(10)
_cell_length_c                   16.416(3)
_cell_measurement_reflns_used    240
_cell_measurement_temperature    290(2)
_cell_measurement_theta_max      32.61
_cell_measurement_theta_min      3.34
_cell_volume                     684.7(2)
_computing_cell_refinement
;
CrysAlisPro, Oxford Diffraction Ltd.,
Version 1.171.33.55 (release 05-01-2010 CrysAlis171 .NET)
(compiled Jan  5 2010,16:28:46)
;
_computing_data_collection
;
CrysAlisPro, Oxford Diffraction Ltd.,
Version 1.171.33.55 (release 05-01-2010 CrysAlis171 .NET)
(compiled Jan  5 2010,16:28:46)
;
_computing_data_reduction
;
CrysAlisPro, Oxford Diffraction Ltd.,
Version 1.171.33.55 (release 05-01-2010 CrysAlis171 .NET)
(compiled Jan  5 2010,16:28:46)
;
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    Sir92
_diffrn_ambient_temperature      290(2)
_diffrn_detector_area_resol_mean 10.3712
_diffrn_measured_fraction_theta_full 0.979
_diffrn_measured_fraction_theta_max 0.980
_diffrn_measurement_device_type  'Xcalibur, Ruby, Gemini ultra'
_diffrn_measurement_method       '\w scans'
_diffrn_radiation_monochromator  mirror
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.0112
_diffrn_reflns_av_sigmaI/netI    0.0096
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_k_max       7
_diffrn_reflns_limit_k_min       -6
_diffrn_reflns_limit_l_max       19
_diffrn_reflns_limit_l_min       -18
_diffrn_reflns_number            4113
_diffrn_reflns_theta_full        67.36
_diffrn_reflns_theta_max         67.36
_diffrn_reflns_theta_min         5.39
_exptl_absorpt_coefficient_mu    0.876
_exptl_absorpt_correction_T_max  0.9175
_exptl_absorpt_correction_T_min  0.8442
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
CrysAlisPro, Oxford Diffraction Ltd.,
Version 1.171.33.55 (release 05-01-2010 CrysAlis171 .NET)
(compiled Jan  5 2010,16:28:46)
Empirical absorption correction using spherical harmonics,
 implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.379
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prism
_exptl_crystal_F_000             304
_exptl_crystal_size_max          0.20
_exptl_crystal_size_mid          0.20
_exptl_crystal_size_min          0.10
_refine_diff_density_max         0.169
_refine_diff_density_min         -0.149
_refine_ls_extinction_coef       0.0125(19)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   1.062
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     100
_refine_ls_number_reflns         1202
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.062
_refine_ls_R_factor_all          0.0358
_refine_ls_R_factor_gt           0.0345
_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^)+(0.0568P)^2^+0.1732P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0977
_refine_ls_wR_factor_ref         0.0989
_reflns_number_gt                1132
_reflns_number_total             1202
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            zb5018.cif
_cod_data_source_block           I
_cod_original_sg_symbol_H-M      'P 21/n'
_cod_database_code               2105048
_cod_database_fobs_code          2105048