1,2-Dihydrobenzocyclobutene-4-carboxylic acid
Feng, Zhi-Qiang; Xu, Bin; Cheng, Wei; Wang, Jin-Tang; Acta Crystallographica Section E 62 (2006) o2646–o2647; doi:10.1107/S1600536806020277

data_2209543
_publ_section_title
;
 1,2-Dihydrobenzocyclobutene-4-carboxylic acid
;
_journal_coeditor_code           HK2052
_journal_issue                   7
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              o2646
_journal_page_last               o2647
_journal_paper_doi               10.1107/S1600536806020277
_journal_volume                  62
_journal_year                    2006
_chemical_formula_iupac          'C9 H8 O2'
_chemical_formula_moiety         'C9 H8 O2'
_chemical_formula_sum            'C9 H8 O2'
_chemical_formula_weight         148.15
_chemical_name_systematic
;
1,2-Dihydroenzocyclobutene-4-carboxylic acid
;
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2yn'
_symmetry_space_group_name_H-M   'P 1 21/n 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                 98.26(2)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   7.233(2)
_cell_length_b                   5.886(3)
_cell_length_c                   17.682(4)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      12
_cell_measurement_theta_min      9
_cell_volume                     745.0(5)
_computing_cell_refinement       'CAD-4 Software'
_computing_data_collection       'CAD-4 Software (Enraf--Nonius, 1989)'
_computing_data_reduction        'XCAD4 (Harms & Wocadlo, 1995)'
_computing_molecular_graphics    SHELXL97
_computing_publication_material  'PLATON (Spek, 2003)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      296(2)
_diffrn_measured_fraction_theta_full 0.987
_diffrn_measured_fraction_theta_max 0.987
_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     0.71073
_diffrn_reflns_av_R_equivalents  0.0349
_diffrn_reflns_av_sigmaI/netI    0.0880
_diffrn_reflns_limit_h_max       8
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       7
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       21
_diffrn_reflns_limit_l_min       -21
_diffrn_reflns_number            1558
_diffrn_reflns_theta_full        25.96
_diffrn_reflns_theta_max         25.96
_diffrn_reflns_theta_min         2.33
_diffrn_standards_decay_%        1
_diffrn_standards_interval_time  120
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    0.093
_exptl_absorpt_correction_T_max  0.9907
_exptl_absorpt_correction_T_min  0.9726
_exptl_absorpt_correction_type   psi-scan
_exptl_absorpt_process_details   '(North <i>et al.</i>,  1968)'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.321
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             312
_exptl_crystal_size_max          0.30
_exptl_crystal_size_mid          0.30
_exptl_crystal_size_min          0.10
_refine_diff_density_max         0.186
_refine_diff_density_min         -0.195
_refine_ls_extinction_coef       0.029(6)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL97
_refine_ls_goodness_of_fit_ref   0.988
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     101
_refine_ls_number_reflns         1440
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.988
_refine_ls_R_factor_all          0.1529
_refine_ls_R_factor_gt           0.0648
_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^)+(0.07P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1362
_refine_ls_wR_factor_ref         0.1781
_reflns_number_gt                675
_reflns_number_total             1440
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            hk2052.cif
_cod_data_source_block           I
_cod_original_cell_volume        745.0(6)
_cod_original_sg_symbol_H-M      'P 21/n'
_cod_database_code               2209543
_cod_database_fobs_code          2209543