4-Methylimidazolium hemisuccinate hemisuccinic acid
Callear, Samantha K.; Hursthouse, Michael B.; Crystal Structure Report Archive  (2008) 473–; doi:

data_1520239
_publ_section_title
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 4-Methylimidazolium hemisuccinate hemisuccinic acid
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_journal_name_full               'Crystal Structure Report Archive'
_journal_page_first              473
_journal_year                    2008
_chemical_formula_sum            'C8 H12 N2 O4'
_chemical_formula_weight         200.20
_chemical_name_systematic
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Succinic acid & 4-methylimidazole
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_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
_cell_angle_alpha                90.00
_cell_angle_beta                 96.299(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   3.9015(2)
_cell_length_b                   17.3293(10)
_cell_length_c                   13.8628(7)
_cell_measurement_reflns_used    2165
_cell_measurement_temperature    120(2)
_cell_measurement_theta_max      27.48
_cell_measurement_theta_min      2.91
_cell_volume                     931.61(9)
_computing_cell_refinement
'DENZO (Otwinowski & Minor, 1997) & COLLECT (Hooft, R.W.W., 1998)'
_computing_data_collection       'COLLECT (Hooft, R.W.W., 1998)'
_computing_data_reduction
'DENZO (Otwinowski & Minor, 1997) & COLLECT (Hooft, R.W.W., 1998)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      120(2)
_diffrn_detector_area_resol_mean 9.091
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.998
_diffrn_measurement_device_type
'Bruker-Nonius 95mm CCD camera on \k-goniostat'
_diffrn_measurement_method       '\f & \w scans'
_diffrn_radiation_monochromator  '10cm confocal mirrors'
_diffrn_radiation_source         'Bruker-Nonius FR591 rotating anode'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0718
_diffrn_reflns_av_sigmaI/netI    0.0599
_diffrn_reflns_limit_h_max       4
_diffrn_reflns_limit_h_min       -5
_diffrn_reflns_limit_k_max       22
_diffrn_reflns_limit_k_min       -22
_diffrn_reflns_limit_l_max       17
_diffrn_reflns_limit_l_min       -17
_diffrn_reflns_number            9780
_diffrn_reflns_theta_full        27.48
_diffrn_reflns_theta_max         27.48
_diffrn_reflns_theta_min         3.18
_exptl_absorpt_coefficient_mu    0.115
_exptl_absorpt_correction_T_max  0.9931
_exptl_absorpt_correction_T_min  0.9886
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS V2.10 (Sheldrick, G.M., 2003)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.427
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             424
_exptl_crystal_size_max          0.10
_exptl_crystal_size_mid          0.07
_exptl_crystal_size_min          0.06
_refine_diff_density_max         0.215
_refine_diff_density_min         -0.264
_refine_diff_density_rms         0.057
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.022
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     132
_refine_ls_number_reflns         2117
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.022
_refine_ls_R_factor_all          0.0744
_refine_ls_R_factor_gt           0.0490
_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^)+(0.0425P)^2^+0.4542P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1057
_refine_ls_wR_factor_ref         0.1169
_reflns_number_gt                1562
_reflns_number_total             2117
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            eCrystal-473.cif
_cod_data_source_block           06skc0051p21c
_cod_depositor_comments
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Citation :
Callear, Samantha K. and Hursthouse, Michael B. (2008) 
University of Southampton, Crystal Structure Report Archive. 
(doi:10.5258/ecrystals/473)

More at:
http://ecrystals.chem.soton.ac.uk/473/
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_cod_original_sg_symbol_H-M      P21/c
_cod_database_code               1520239