Na~7~Al~3~(As~2~O~7~)~4~
Fakhar Bourguiba, Noura; Driss, Ahmed; Acta Crystallographica Section E 69 (2013) i53–; doi:10.1107/S1600536813020151

data_2238357
_publ_section_title
;
 Na~7~Al~3~(As~2~O~7~)~4~
;
_journal_coeditor_code           HB7105
_journal_issue                   8
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              i53
_journal_paper_doi               10.1107/S1600536813020151
_journal_volume                  69
_journal_year                    2013
_chemical_formula_iupac          'Na7 Al3 (As2 O7)4'
_chemical_formula_moiety         'Al3 As8 Na7 O28'
_chemical_formula_sum            'Al3 As8 Na7 O28'
_chemical_formula_weight         1289.23
_chemical_name_systematic
;
Heptasodium trialuminium tetrakis(diarsenate)
;
_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_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 94.140(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   9.8000(10)
_cell_length_b                   8.4680(10)
_cell_length_c                   28.637(2)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    298(2)
_cell_measurement_theta_max      15
_cell_measurement_theta_min      10
_cell_volume                     2370.3(4)
_computing_cell_refinement
'CAD-4 EXPRESS (Duisenberg, 1992; Mac\'i\<cek & Yordanov, 1992)'
_computing_data_collection
'CAD-4 EXPRESS (Duisenberg, 1992; Mac\'i\<cek & Yordanov, 1992)'
_computing_data_reduction        'XCAD4 (Harms & Wocadlo, 1995)'
_computing_molecular_graphics    'DIAMOND (Brandenburg, 1998)'
_computing_publication_material  'WinGX (Farrugia, 2012)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      298(2)
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.998
_diffrn_measurement_device_type  'Enraf--Nonius CAD-4'
_diffrn_measurement_method       \w/2\q
_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  0.0560
_diffrn_reflns_av_sigmaI/netI    0.0485
_diffrn_reflns_limit_h_max       3
_diffrn_reflns_limit_h_min       -12
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       -1
_diffrn_reflns_limit_l_max       36
_diffrn_reflns_limit_l_min       -36
_diffrn_reflns_number            3958
_diffrn_reflns_theta_full        26.98
_diffrn_reflns_theta_max         26.98
_diffrn_reflns_theta_min         2.85
_diffrn_standards_decay_%        1.1
_diffrn_standards_interval_time  120
_diffrn_standards_number         2
_exptl_absorpt_coefficient_mu    11.504
_exptl_absorpt_correction_T_max  0.891
_exptl_absorpt_correction_T_min  0.759
_exptl_absorpt_correction_type   psi-scan
_exptl_absorpt_process_details   '(North <i>et al.</i>, 1968)'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    3.613
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       parallelipiped
_exptl_crystal_F_000             2416
_exptl_crystal_size_max          0.25
_exptl_crystal_size_mid          0.20
_exptl_crystal_size_min          0.1
_refine_diff_density_max         1.265
_refine_diff_density_min         -0.978
_refine_ls_extinction_coef       0.00057(6)
_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   1.100
_refine_ls_matrix_type           full
_refine_ls_number_parameters     221
_refine_ls_number_reflns         2583
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.100
_refine_ls_R_factor_all          0.0496
_refine_ls_R_factor_gt           0.0336
_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^)+(0.0314P)^2^+24.9095P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0791
_refine_ls_wR_factor_ref         0.0845
_reflns_number_gt                2150
_reflns_number_total             2583
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            hb7105.cif
_cod_data_source_block           I
_cod_original_sg_symbol_H-M      'C 2/c'
_cod_database_code               2238357
_cod_database_fobs_code          2238357