<i>R</i>_<b>4</b>^<b>4</b>(30) rectangular rings in 2,5-dioxopiperazine-1,4-diacetic acid
Ramos Silva, Manuela; Matos Beja, Ana; Paixao, Jose Antonio; Sobral, Abilio J. F. N.; Cabral, Lucia M. L.; Rocha Gonsalves, A. M. dA.; Acta Crystallographica Section C 59 (2003) o562–o563; doi:10.1107/S0108270103017803

data_2013568
_publ_section_title
;
 <i>R</i>_<b>4</b>^<b>4</b>(30) rectangular rings in
 2,5-dioxopiperazine-1,4-diacetic acid
;
_journal_issue                   10
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              o562
_journal_page_last               o563
_journal_paper_doi               10.1107/S0108270103017803
_journal_volume                  59
_journal_year                    2003
_chemical_formula_iupac          'C8 H10 N2 O6'
_chemical_formula_moiety         'C8 H10 N2 O6'
_chemical_formula_sum            'C8 H10 N2 O6'
_chemical_formula_weight         230.18
_chemical_name_systematic
;
2,5-dioxopiperazine-1,4-diacetic acid
;
_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   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 108.189(7)
_cell_angle_gamma                90.00
_cell_formula_units_Z            2
_cell_length_a                   5.5322(6)
_cell_length_b                   9.1505(13)
_cell_length_c                   9.8235(8)
_cell_measurement_reflns_used    14
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      13.64
_cell_measurement_theta_min      7.73
_cell_volume                     472.44(9)
_computing_cell_refinement       'CAD-4 Software'
_computing_data_collection       'CAD-4 Software (Enraf--Nonius, 1989)'
_computing_data_reduction        'HELENA (Spek, 1997)'
_computing_molecular_graphics    'ORTEPII (Johnson, 1976)'
_computing_publication_material  SHELXL97
_computing_structure_refinement  'SHELXL97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'Enraf-Nonius CAD-4 diffractometer'
_diffrn_measurement_method       'profile data from \w-2\q scans'
_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  0.0453
_diffrn_reflns_av_sigmaI/netI    0.0332
_diffrn_reflns_limit_h_max       6
_diffrn_reflns_limit_h_min       -6
_diffrn_reflns_limit_k_max       11
_diffrn_reflns_limit_k_min       -11
_diffrn_reflns_limit_l_max       11
_diffrn_reflns_limit_l_min       -11
_diffrn_reflns_number            2943
_diffrn_reflns_theta_full        25.48
_diffrn_reflns_theta_max         25.48
_diffrn_reflns_theta_min         3.12
_diffrn_standards_decay_%        3
_diffrn_standards_interval_time  180
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    0.141
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.618
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             240
_exptl_crystal_size_max          0.27
_exptl_crystal_size_mid          0.23
_exptl_crystal_size_min          0.09
_refine_diff_density_max         0.311
_refine_diff_density_min         -0.261
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.051
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     76
_refine_ls_number_reflns         872
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.051
_refine_ls_R_factor_all          0.0729
_refine_ls_R_factor_gt           0.0421
_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^)+(0.0482P)^2^+0.2592P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1034
_refine_ls_wR_factor_ref         0.1168
_reflns_number_gt                604
_reflns_number_total             872
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            fa1026.cif
_cod_data_source_block           I
_cod_original_sg_symbol_H-M      'P 21/c'
_cod_database_code               2013568
_cod_database_fobs_code          2013568