The monoclinic polymorph of dimethylarsinic acid
Betz, Richard; McCleland, Cedric; Marchand, Harold; Acta Crystallographica Section E 67 (2011) m1013–; doi:10.1107/S1600536811025505

data_2231343
_publ_section_title
;
 The monoclinic polymorph of dimethylarsinic acid
;
_journal_coeditor_code           WM2504
_journal_issue                   8
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              m1013
_journal_paper_doi               10.1107/S1600536811025505
_journal_volume                  67
_journal_year                    2011
_chemical_formula_iupac          '[As (C H3)2 O (O H)]'
_chemical_formula_moiety         'C2 H7 As O2'
_chemical_formula_sum            'C2 H7 As O2'
_chemical_formula_weight         138.00
_chemical_melting_point_gt       468
_chemical_melting_point_lt       469
_chemical_name_common
;
Cacodylic acid
;
_chemical_name_systematic
;
dimethylarsinic acid
;
_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
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 125.86(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   15.764(9)
_cell_length_b                   6.494(5)
_cell_length_c                   11.302(4)
_cell_measurement_reflns_used    6920
_cell_measurement_temperature    200(2)
_cell_measurement_theta_max      28.35
_cell_measurement_theta_min      2.22
_cell_volume                     937.7(10)
_computing_cell_refinement       'SAINT (Bruker, 2010)'
_computing_data_collection       'APEX2 (Bruker, 2010)'
_computing_data_reduction        'SAINT (Bruker, 2010)'
_computing_molecular_graphics
'ORTEP-3 (Farrugia, 1997) and Mercury (Macrae <i>et al.</i>, 2008)'
_computing_publication_material
'SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      200(2)
_diffrn_measured_fraction_theta_full 0.991
_diffrn_measured_fraction_theta_max 0.991
_diffrn_measurement_device_type  'Bruker APEXII CCD'
_diffrn_measurement_method       '\f and \w'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71069
_diffrn_reflns_av_R_equivalents  0.0403
_diffrn_reflns_av_sigmaI/netI    0.0214
_diffrn_reflns_limit_h_max       20
_diffrn_reflns_limit_h_min       -20
_diffrn_reflns_limit_k_max       7
_diffrn_reflns_limit_k_min       -8
_diffrn_reflns_limit_l_max       15
_diffrn_reflns_limit_l_min       -15
_diffrn_reflns_number            7792
_diffrn_reflns_theta_full        28.35
_diffrn_reflns_theta_max         28.35
_diffrn_reflns_theta_min         3.52
_exptl_absorpt_coefficient_mu    7.092
_exptl_absorpt_correction_T_max  1.0000
_exptl_absorpt_correction_T_min  0.6078
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '(<i>SADABS</i>; Bruker, 2008)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.955
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             544
_exptl_crystal_size_max          0.49
_exptl_crystal_size_mid          0.42
_exptl_crystal_size_min          0.39
_refine_diff_density_max         0.306
_refine_diff_density_min         -0.800
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.203
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     49
_refine_ls_number_reflns         1166
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.203
_refine_ls_R_factor_all          0.0215
_refine_ls_R_factor_gt           0.0204
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0242P)^2^+1.2973P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0544
_refine_ls_wR_factor_ref         0.0551
_reflns_number_gt                1117
_reflns_number_total             1166
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            wm2504.cif
_cod_data_source_block           I
_cod_original_sg_symbol_H-M      'C 2/c'
_cod_database_code               2231343
_cod_database_fobs_code          2231343