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_2103719
_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         'C5 H7 N2, C4 H O4'
_chemical_formula_sum            'C9 H8 N2 O4'
_chemical_formula_weight         208.18
_chemical_name_systematic
;
3-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                100.78(2)
_cell_angle_beta                 91.66(2)
_cell_angle_gamma                88.26(2)
_cell_formula_units_Z            4
_cell_length_a                   3.8120(10)
_cell_length_b                   11.012(2)
_cell_length_c                   21.942(5)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      13
_cell_measurement_theta_min      8
_cell_volume                     904.1(4)
_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    'ORTEP II (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 .994
_diffrn_measured_fraction_theta_max .994
_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  .022
_diffrn_reflns_av_sigmaI/netI    .0430
_diffrn_reflns_limit_h_max       4
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       14
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       27
_diffrn_reflns_limit_l_min       -28
_diffrn_reflns_number            4454
_diffrn_reflns_theta_full        27.00
_diffrn_reflns_theta_max         27.00
_diffrn_reflns_theta_min         2.26
_diffrn_standards_interval_time  120
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    .123
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            'pale yellow'
_exptl_crystal_density_diffrn    1.529
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prism
_exptl_crystal_F_000             432
_exptl_crystal_size_max          .52
_exptl_crystal_size_mid          .30
_exptl_crystal_size_min          .14
_refine_diff_density_max         .347
_refine_diff_density_min         -.388
_refine_ls_extinction_coef       .011(4)
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   1.056
_refine_ls_hydrogen_treatment    refall
_refine_ls_matrix_type           full
_refine_ls_number_parameters     336
_refine_ls_number_reflns         3913
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.056
_refine_ls_R_factor_all          .1066
_refine_ls_R_factor_gt           .0640
_refine_ls_shift/su_max          .018
_refine_ls_shift/su_mean         .002
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.1236P)^2^+0.1121P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_ref         .2029
_reflns_number_gt                2471
_reflns_number_total             3913
_reflns_threshold_expression     I>2sigma(I)
_cod_data_source_file            na0121.cif
_cod_data_source_block           2
_cod_database_code               2103719
_cod_database_fobs_code          2103719