Mg~6.75~(OH)~3~(H~0.166~AsO~4~)~3~(HAsO~4~), a member of the <i>M</i>~1-~<i>~x~M</i>'~6~(OH)~3~(H~2<i>x~/3</i>AsO~4~)~3~(HAsO~4~) family (<i>M</i>,<i>M</i>' = Co; Ni)
Weil, Matthias; Acta Crystallographica Section E 69 (2013) i29–; doi:10.1107/S1600536813010714

data_2238069
_publ_section_title
;
 Mg~6.75~(OH)~3~(H~0.166~AsO~4~)~3~(HAsO~4~), a member of the
 <i>M</i>~1-~<i>~x~M</i>'~6~(OH)~3~(H~2<i>x~/3</i>AsO~4~)~3~(HAsO~4~)
 family (<i>M</i>,<i>M</i>' = Co; Ni)
;
_journal_coeditor_code           VN2069
_journal_issue                   5
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              i29
_journal_paper_doi               10.1107/S1600536813010714
_journal_volume                  69
_journal_year                    2013
_chemical_formula_iupac          'Mg6.75 (O H)3 (H0.166 As O4)3 (H As O4)'
_chemical_formula_structural     'Mg6.75 (O H)3 (H0.166 As O4)3 (H As O4)'
_chemical_formula_sum            'As4 H4.5 Mg6.75 O19'
_chemical_formula_weight         772.31
_chemical_name_systematic
;
Magnesium hydroxide hydrogenarsenate (6.75/3/4)
;
_space_group_IT_number           186
_symmetry_cell_setting           hexagonal
_symmetry_space_group_name_Hall  'P 6c -2c'
_symmetry_space_group_name_H-M   'P 63 m c'
_atom_sites_solution_primary     isomor
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                120.00
_cell_formula_units_Z            2
_cell_length_a                   12.7651(3)
_cell_length_b                   12.7651(3)
_cell_length_c                   5.08440(10)
_cell_measurement_reflns_used    5443
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      34.407
_cell_measurement_theta_min      6.192
_cell_volume                     717.49(3)
_computing_cell_refinement       'SAINT (Bruker, 2008)'
_computing_data_collection       'APEX2 (Bruker, 2008)'
_computing_data_reduction        'SAINT (Bruker, 2008)'
_computing_molecular_graphics    'ATOMS for Windows (Dowty, 2006)'
_computing_publication_material  'publCIF (Westrip, 2010)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      296(2)
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device_type  'Bruker APEXII CCD'
_diffrn_measurement_method       '\w and \f scans'
_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  0.0511
_diffrn_reflns_av_sigmaI/netI    0.0269
_diffrn_reflns_limit_h_max       21
_diffrn_reflns_limit_h_min       -21
_diffrn_reflns_limit_k_max       21
_diffrn_reflns_limit_k_min       -21
_diffrn_reflns_limit_l_max       8
_diffrn_reflns_limit_l_min       -5
_diffrn_reflns_number            21473
_diffrn_reflns_theta_full        36.21
_diffrn_reflns_theta_max         36.21
_diffrn_reflns_theta_min         1.84
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    9.649
_exptl_absorpt_correction_T_max  0.8304
_exptl_absorpt_correction_T_min  0.1599
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '(<i>SADABS</i>; Bruker, 2008)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    3.575
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             739
_exptl_crystal_size_max          0.30
_exptl_crystal_size_mid          0.02
_exptl_crystal_size_min          0.02
_refine_diff_density_max         1.308
_refine_diff_density_min         -2.164
_refine_ls_abs_structure_details 'Flack (1983), 446 Friedel pairs'
_refine_ls_abs_structure_Flack   0.022(16)
_refine_ls_extinction_coef       0.0015(4)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     'SHELXL97 (Sheldrick, 2008)'
_refine_ls_goodness_of_fit_ref   1.205
_refine_ls_hydrogen_treatment    noref
_refine_ls_matrix_type           full
_refine_ls_number_parameters     60
_refine_ls_number_reflns         1144
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.205
_refine_ls_R_factor_all          0.0329
_refine_ls_R_factor_gt           0.0291
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0061P)^2^+2.8884P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0568
_refine_ls_wR_factor_ref         0.0575
_reflns_number_gt                1066
_reflns_number_total             1144
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            vn2069.cif
_cod_data_source_block           I
_cod_original_formula_sum        'As4 H4.50 Mg6.75 O19'
_cod_database_code               2238069
_cod_database_fobs_code          2238069