The Discovery of New Crystal Forms of 5-Fluorocytosine Consistent with the Results of Computational Crystal Structure Prediction
Hulme, Ashley T.; Tocher, Derek A.; Crystal Growth & Design 6 (2006) 481–487; doi:10.1021/cg050398g

data_4504659
_publ_section_title
;
 The Discovery of New Crystal Forms of 5-Fluorocytosine Consistent with
 the Results of Computational Crystal Structure Prediction
;
_journal_coden_ASTM              CGDEFU
_journal_issue                   2
_journal_name_full               'Crystal Growth & Design'
_journal_page_first              481
_journal_page_last               487
_journal_paper_doi               10.1021/cg050398g
_journal_volume                  6
_journal_year                    2006
_chemical_formula_moiety         '2(C4 H4 F N3 O), 5(H2 O)'
_chemical_formula_sum            'C4 H9 F N3 O3.5'
_chemical_formula_weight         348.28
_chemical_name_systematic
;
 5-fluorocytosine hemipentahydrate
;
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/c 1'
_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                 111.3910(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   12.2384(8)
_cell_length_b                   9.4254(6)
_cell_length_c                   13.8727(9)
_cell_measurement_reflns_used    7923
_cell_measurement_temperature    150(2)
_cell_measurement_theta_max      28.2805
_cell_measurement_theta_min      2.675
_cell_volume                     1490.01(17)
_computing_cell_refinement       'Bruker SAINT'
_computing_data_collection       'Bruker SMART'
_computing_data_reduction        'Bruker SAINT'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      150(2)
_diffrn_measured_fraction_theta_full 0.994
_diffrn_measured_fraction_theta_max 0.956
_diffrn_measurement_device_type  'Bruker SMART APEX diffractometer'
_diffrn_measurement_method       '\w rotation with narrow frames'
_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  0.0168
_diffrn_reflns_av_sigmaI/netI    0.0151
_diffrn_reflns_limit_h_max       16
_diffrn_reflns_limit_h_min       -15
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -12
_diffrn_reflns_limit_l_max       18
_diffrn_reflns_limit_l_min       -17
_diffrn_reflns_number            12658
_diffrn_reflns_theta_full        26.00
_diffrn_reflns_theta_max         28.28
_diffrn_reflns_theta_min         2.68
_diffrn_standards_decay_%        0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.148
_exptl_absorpt_correction_T_max  0.9603
_exptl_absorpt_correction_T_min  0.9068
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS (Sheldrick, 1996)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.553
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             728
_exptl_crystal_size_max          0.67
_exptl_crystal_size_mid          0.53
_exptl_crystal_size_min          0.28
_refine_diff_density_max         0.373
_refine_diff_density_min         -0.303
_refine_diff_density_rms         0.066
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.130
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     277
_refine_ls_number_reflns         3539
_refine_ls_number_restraints     15
_refine_ls_restrained_S_all      1.131
_refine_ls_R_factor_all          0.0462
_refine_ls_R_factor_gt           0.0443
_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^)+(0.0656P)^2^+0.6931P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1301
_refine_ls_wR_factor_ref         0.1316
_reflns_number_gt                3311
_reflns_number_total             3539
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            cg050398gsi20050809_092810.cif
_cod_data_source_block           str0281
_cod_original_sg_symbol_Hall     -P2ybc
_cod_original_sg_symbol_H-M      P21/c
_cod_database_code               4504659