Redetermination of iron(III) arsenate dihydrate
Yan Xu; Guang-Peng Zhou; Xue-Fang Zheng; Acta Crystallographica Section E 63 (2007) i67–i69; doi:10.1107/S1600536807005302

data_2212542
_publ_section_title
;
 Redetermination of iron(III) arsenate dihydrate
;
_journal_coeditor_code           FI2026
_journal_issue                   3
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              i67
_journal_page_last               i69
_journal_paper_doi               10.1107/S1600536807005302
_journal_volume                  63
_journal_year                    2007
_chemical_compound_source        Synthetic
_chemical_formula_iupac          'Fe (As O4), 2H2 O1'
_chemical_formula_moiety         'As Fe H4 O6'
_chemical_formula_sum            'As Fe H4 O6'
_chemical_formula_weight         230.80
_chemical_name_mineral           Scorodite
_chemical_name_systematic
;
iron(III) arsenate dihydrate
;
_space_group_IT_number           61
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  '-P 2ac 2ab'
_symmetry_space_group_name_H-M   'P b c a'
_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                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   8.942(7)
_cell_length_b                   10.075(8)
_cell_length_c                   10.339(8)
_cell_measurement_reflns_used    4587
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      25.98
_cell_measurement_theta_min      3.63
_cell_volume                     931.4(13)
_computing_cell_refinement       'SAINT (Bruker, 2005)'
_computing_data_collection       'APEX2 (Bruker, 2005)'
_computing_data_reduction        SAINT
_computing_molecular_graphics    'SHELXTL (Sheldrick, 1997b)'
_computing_publication_material  SHELXTL
_computing_structure_refinement  'SHELXL97 (Sheldrick, 1997a)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 1997a)'
_database_code_amcsd             0010474
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'Bruker APEX2 CCD'
_diffrn_measurement_method       \w
_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  0.0474
_diffrn_reflns_av_sigmaI/netI    0.0358
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -11
_diffrn_reflns_limit_k_max       11
_diffrn_reflns_limit_k_min       -12
_diffrn_reflns_limit_l_max       12
_diffrn_reflns_limit_l_min       -12
_diffrn_reflns_number            4587
_diffrn_reflns_theta_full        25.98
_diffrn_reflns_theta_max         25.98
_diffrn_reflns_theta_min         3.63
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    10.226
_exptl_absorpt_correction_T_max  0.3133
_exptl_absorpt_correction_T_min  0.2592
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '(SADABS; Sheldrick, 2003)'
_exptl_crystal_colour            Green
_exptl_crystal_density_diffrn    3.291
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       Block
_exptl_crystal_F_000             888
_exptl_crystal_size_max          0.15
_exptl_crystal_size_mid          0.12
_exptl_crystal_size_min          0.12
_refine_diff_density_max         0.787
_refine_diff_density_min         -0.524
_refine_ls_extinction_coef       0.0074(5)
_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   1.116
_refine_ls_hydrogen_treatment    refxyz
_refine_ls_matrix_type           full
_refine_ls_number_parameters     86
_refine_ls_number_reflns         915
_refine_ls_number_restraints     4
_refine_ls_restrained_S_all      1.115
_refine_ls_R_factor_all          0.0296
_refine_ls_R_factor_gt           0.0244
_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^)+(0.0271P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0572
_refine_ls_wR_factor_ref         0.0593
_reflns_number_gt                805
_reflns_number_total             915
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            fi2026.cif
_cod_data_source_block           I
_cod_original_cell_volume        931.5(12)
_cod_original_formula_sum        ' As Fe H4 O6'
_cod_database_code               2212542
_cod_database_fobs_code          2212542