General rules for the packing of hydrogen-bonded crystals as derived from the analysis of squaric acid anions: aminoaromatic nitrogen base co-crystals
Bertolasi, Valerio; Gilli, Paola; Ferretti, Valeria; Gilli, Gastone; Acta Crystallographica Section B 57 (2001) 591–598; doi:10.1107/S010876810100814X

data_2103718
_publ_section_title
;
 General rules for the packing of hydrogen-bonded crystals as derived
 from the analysis of squaric acid anions: aminoaromatic nitrogen base
 co-crystals
;
_journal_issue                   4
_journal_name_full               'Acta Crystallographica Section B'
_journal_page_first              591
_journal_page_last               598
_journal_paper_doi               10.1107/S010876810100814X
_journal_volume                  57
_journal_year                    2001
_chemical_formula_moiety         'C4 H6 N3, C4 H O4'
_chemical_formula_sum            'C8 H7 N3 O4'
_chemical_formula_weight         209.17
_chemical_name_systematic
;
2-aminopyridinium hydrogen squarate, 1:1
;
_space_group_IT_number           2
_symmetry_cell_setting           triclinic
_symmetry_space_group_name_Hall  '-P 1'
_symmetry_space_group_name_H-M   'P -1'
_audit_creation_method           SHELXL-97
_cell_angle_alpha                99.72(2)
_cell_angle_beta                 104.05(2)
_cell_angle_gamma                87.730(10)
_cell_formula_units_Z            2
_cell_length_a                   8.2790(10)
_cell_length_b                   10.1840(10)
_cell_length_c                   5.353(2)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      14
_cell_measurement_theta_min      8
_cell_volume                     431.54(18)
_computing_cell_refinement       'CAD4 Enraf-Nonius, 1984'
_computing_data_collection       'CAD4 (Enraf-Nonius, 1984)'
_computing_data_reduction        'MolEN (Fair, 1990; Enraf-Nonius, 1990)'
_computing_molecular_graphics    'ORTEPII (Johnson, 1976)'
_computing_publication_material
;
PARST (Nardelli, 1983, 1995),  SHELXL-97 (Sheldrick, 1997)
;
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SIR92 (Altomare et al., 1994)'
_diffrn_ambient_temperature      296(2)
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device_type  'Enraf-Nonius CAD-4'
_diffrn_measurement_method       \w/2\q
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     .71073
_diffrn_reflns_av_R_equivalents  .013
_diffrn_reflns_av_sigmaI/netI    .0230
_diffrn_reflns_limit_h_max       10
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       6
_diffrn_reflns_limit_l_min       -7
_diffrn_reflns_number            2769
_diffrn_reflns_theta_full        28.00
_diffrn_reflns_theta_max         28.00
_diffrn_reflns_theta_min         2.03
_diffrn_standards_decay_%        0
_diffrn_standards_interval_time  120
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    .132
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.610
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             216
_exptl_crystal_size_max          .52
_exptl_crystal_size_mid          .36
_exptl_crystal_size_min          .10
_refine_diff_density_max         .341
_refine_diff_density_min         -.330
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.016
_refine_ls_hydrogen_treatment    refall
_refine_ls_matrix_type           full
_refine_ls_number_parameters     164
_refine_ls_number_reflns         2078
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.016
_refine_ls_R_factor_all          .0659
_refine_ls_R_factor_gt           .0498
_refine_ls_shift/su_max          .003
_refine_ls_shift/su_mean         .000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.1114P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_ref         .1496
_reflns_number_gt                1596
_reflns_number_total             2078
_reflns_threshold_expression     I>2sigma(I)
_cod_data_source_file            na0121.cif
_cod_data_source_block           1
_cod_original_cell_volume        431.5(2)
_cod_database_code               2103718
_cod_database_fobs_code          2103718