5,5-Dihydroxybarbituric acid monohydrate (alloxan dihydrate)
Thomas C. Lewis; Derek A. Tocher; Acta Crystallographica Section E 60 (2004) o1689–o1690; doi:10.1107/S1600536804021555

data_2204264
_publ_section_title
;
 5,5-Dihydroxybarbituric acid monohydrate (alloxan dihydrate)
;
_journal_issue                   10
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              o1689
_journal_page_last               o1690
_journal_paper_doi               10.1107/S1600536804021555
_journal_volume                  60
_journal_year                    2004
_chemical_formula_iupac          'C4 H4 N2 O5, H2 O1'
_chemical_formula_moiety         'C4 H4 N2 O5, H2 O1'
_chemical_formula_sum            'C4 H6 N2 O6'
_chemical_formula_weight         178.11
_chemical_name_systematic
;
5,5-dihydroxybarbituric acid monohydrate
;
_space_group_IT_number           2
_symmetry_cell_setting           triclinic
_symmetry_space_group_name_Hall  '-P 1'
_symmetry_space_group_name_H-M   'P -1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_cell_angle_alpha                105.401(3)
_cell_angle_beta                 93.134(3)
_cell_angle_gamma                115.089(2)
_cell_formula_units_Z            2
_cell_length_a                   6.6730(11)
_cell_length_b                   7.5834(13)
_cell_length_c                   7.6157(13)
_cell_measurement_reflns_used    712
_cell_measurement_temperature    150(2)
_cell_measurement_theta_max      25.02
_cell_measurement_theta_min      2.83
_cell_volume                     330.26(10)
_computing_cell_refinement       SAINT
_computing_data_collection       'SMART (Bruker, 2000)'
_computing_data_reduction        'SAINT (Bruker, 2000)'
_computing_molecular_graphics    '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 0.995
_diffrn_measured_fraction_theta_max 0.942
_diffrn_measurement_device_type  'Bruker SMART APEX'
_diffrn_measurement_method       '\w rotation scans 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  0.0208
_diffrn_reflns_av_sigmaI/netI    0.0381
_diffrn_reflns_limit_h_max       8
_diffrn_reflns_limit_h_min       -8
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       -9
_diffrn_reflns_limit_l_max       10
_diffrn_reflns_limit_l_min       -10
_diffrn_reflns_number            2972
_diffrn_reflns_theta_full        26.00
_diffrn_reflns_theta_max         28.28
_diffrn_reflns_theta_min         2.83
_diffrn_standards_decay_%        0
_diffrn_standards_interval_count 0
_diffrn_standards_interval_time  0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.172
_exptl_absorpt_correction_T_max  0.9881
_exptl_absorpt_correction_T_min  0.9615
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '(SADABS; Sheldrick, 1996)'
_exptl_crystal_colour            Colourless
_exptl_crystal_density_diffrn    1.791
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       Plate
_exptl_crystal_F_000             184
_exptl_crystal_size_max          0.23
_exptl_crystal_size_mid          0.11
_exptl_crystal_size_min          0.07
_refine_diff_density_max         0.343
_refine_diff_density_min         -0.236
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.072
_refine_ls_hydrogen_treatment    refall
_refine_ls_matrix_type           full
_refine_ls_number_parameters     133
_refine_ls_number_reflns         1536
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.072
_refine_ls_R_factor_all          0.0545
_refine_ls_R_factor_gt           0.0427
_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^)+(0.0502P)^2^+0.0119P] where P = (Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0960
_refine_ls_wR_factor_ref         0.1021
_reflns_number_gt                1274
_reflns_number_total             1536
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            bt6506.cif
_cod_data_source_block           I
_cod_database_code               2204264
_cod_database_fobs_code          2204264