Redetermination of 5,5-dihydroxybarbituric acid trihydrate (alloxan tetrahydrate)
Thomas C. Lewis; Derek A. Tocher; Acta Crystallographica Section E 60 (2004) o1748–o1750; doi:10.1107/S1600536804022019

data_2204265
_publ_section_title
;
 Redetermination of 5,5-dihydroxybarbituric acid trihydrate (alloxan
 tetrahydrate)
;
_journal_issue                   10
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              o1748
_journal_page_last               o1750
_journal_paper_doi               10.1107/S1600536804022019
_journal_volume                  60
_journal_year                    2004
_chemical_formula_moiety         'C4 H4 N2 O5, 3H2 O'
_chemical_formula_sum            'C4 H10 N2 O8'
_chemical_formula_weight         214.14
_chemical_name_systematic
;
5,5-dihydroxybarbituric acid trihydrate
;
_space_group_IT_number           12
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-C 2y'
_symmetry_space_group_name_H-M   'C 1 2/m 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_cell_angle_alpha                90.00
_cell_angle_beta                 91.4650(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   9.4614(8)
_cell_length_b                   12.2095(10)
_cell_length_c                   7.2973(6)
_cell_measurement_reflns_used    3125
_cell_measurement_temperature    150(2)
_cell_measurement_theta_max      28.22
_cell_measurement_theta_min      2.72
_cell_volume                     842.70(12)
_computing_cell_refinement       'SAINT (Bruker, 2000)'
_computing_data_collection       'SMART (Bruker, 2000)'
_computing_data_reduction        SAINT
_computing_molecular_graphics
;
Mercury (Bruno et al., 2002) and SHELXTL (Bruker, 2000)
;
_computing_publication_material  SHELXL97
_computing_structure_refinement  'SHELXL97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      150(2)
_diffrn_measured_fraction_theta_full 0.985
_diffrn_measured_fraction_theta_max 0.953
_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  0.0145
_diffrn_reflns_av_sigmaI/netI    0.0128
_diffrn_reflns_limit_h_max       12
_diffrn_reflns_limit_h_min       -12
_diffrn_reflns_limit_k_max       15
_diffrn_reflns_limit_k_min       -15
_diffrn_reflns_limit_l_max       9
_diffrn_reflns_limit_l_min       -9
_diffrn_reflns_number            3701
_diffrn_reflns_theta_full        26.00
_diffrn_reflns_theta_max         28.22
_diffrn_reflns_theta_min         2.72
_diffrn_standards_decay_%        0
_diffrn_standards_interval_count 0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.167
_exptl_absorpt_correction_T_max  0.9819
_exptl_absorpt_correction_T_min  0.8893
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '(SADABS; Sheldrick, 1996)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.688
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             448
_exptl_crystal_size_max          0.72
_exptl_crystal_size_mid          0.62
_exptl_crystal_size_min          0.11
_refine_diff_density_max         0.411
_refine_diff_density_min         -0.237
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.116
_refine_ls_hydrogen_treatment    refall
_refine_ls_matrix_type           full
_refine_ls_number_parameters     100
_refine_ls_number_reflns         1036
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.116
_refine_ls_R_factor_all          0.0286
_refine_ls_R_factor_gt           0.0283
_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^)+(0.0445P)^2^+0.3397P] where P = (Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0771
_refine_ls_wR_factor_ref         0.0775
_reflns_number_gt                1019
_reflns_number_total             1036
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            bt6507.cif
_cod_data_source_block           I
_cod_original_sg_symbol_H-M      C2/m
_cod_database_code               2204265
_cod_database_fobs_code          2204265