4-Methylimidazolium hemioxalate hydrate
Callear, Samantha K.; Hursthouse, Michael B.; Crystal Structure Report Archive  (2008) 490–; doi:

data_1520151
_publ_section_title
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 4-Methylimidazolium hemioxalate hydrate
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_journal_name_full               'Crystal Structure Report Archive'
_journal_page_first              490
_journal_year                    2008
_chemical_formula_sum            'C10 H16 N4 O5'
_chemical_formula_weight         272.27
_chemical_name_systematic
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Oxalic acid & 4-methylimidazole hydrate
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_space_group_IT_number           15
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-C 2yc'
_symmetry_space_group_name_H-M   'C 1 2/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                 99.252(4)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   9.1937(6)
_cell_length_b                   13.5734(6)
_cell_length_c                   10.5047(5)
_cell_measurement_reflns_used    2929
_cell_measurement_temperature    120(2)
_cell_measurement_theta_max      27.48
_cell_measurement_theta_min      2.91
_cell_volume                     1293.83(12)
_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 0.999
_diffrn_measured_fraction_theta_max 0.999
_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  0.1136
_diffrn_reflns_av_sigmaI/netI    0.0517
_diffrn_reflns_limit_h_max       11
_diffrn_reflns_limit_h_min       -11
_diffrn_reflns_limit_k_max       17
_diffrn_reflns_limit_k_min       -17
_diffrn_reflns_limit_l_max       13
_diffrn_reflns_limit_l_min       -13
_diffrn_reflns_number            14887
_diffrn_reflns_theta_full        27.47
_diffrn_reflns_theta_max         27.47
_diffrn_reflns_theta_min         3.00
_exptl_absorpt_coefficient_mu    0.113
_exptl_absorpt_correction_T_max  0.9977
_exptl_absorpt_correction_T_min  0.9833
_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    1.398
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       fragment
_exptl_crystal_F_000             576
_exptl_crystal_size_max          0.15
_exptl_crystal_size_mid          0.07
_exptl_crystal_size_min          0.02
_refine_diff_density_max         0.297
_refine_diff_density_min         -0.304
_refine_diff_density_rms         0.068
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.072
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     92
_refine_ls_number_reflns         1488
_refine_ls_number_restraints     2
_refine_ls_restrained_S_all      1.079
_refine_ls_R_factor_all          0.0664
_refine_ls_R_factor_gt           0.0485
_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^)+(0.0361P)^2^+1.4019P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1051
_refine_ls_wR_factor_ref         0.1131
_reflns_number_gt                1187
_reflns_number_total             1488
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            eCrystal-490.cif
_cod_data_source_block           06skc0053c2c
_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/490)

More at:
http://ecrystals.chem.soton.ac.uk/490/
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_cod_original_sg_symbol_H-M      C2/c
_cod_database_code               1520151