K~0.8~Ag~0.2~Nb~4~O~9~AsO~4~
Ben Amor, Rym; Zid, Mohamed Faouzi; Driss, Ahmed; Acta Crystallographica Section E 64 (2008) i41–; doi:10.1107/S1600536808015225

data_2218402
_publ_section_title
;
 K~0.8~Ag~0.2~Nb~4~O~9~AsO~4~
;
_journal_coeditor_code           FJ2116
_journal_issue                   6
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              i41
_journal_paper_doi               10.1107/S1600536808015225
_journal_volume                  64
_journal_year                    2008
_chemical_formula_iupac          'K0.8 Ag0.2 Nb4 O9 As O4'
_chemical_formula_moiety         'Ag0.2 As K0.8 Nb4 O13'
_chemical_formula_structural     'K0.8 Ag0.2 Nb4 O9 As O4'
_chemical_formula_sum            'Ag0.2 As K0.8 Nb4 O13'
_chemical_formula_weight         707.41
_chemical_name_systematic
;
Potassium silver tetraniobium nonaoxide arsenate
;
_space_group_IT_number           63
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  '-C 2c 2'
_symmetry_space_group_name_H-M   'C m c m'
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL97
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   10.469(2)
_cell_length_b                   10.403(2)
_cell_length_c                   10.0470(10)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    298(2)
_cell_measurement_theta_max      16
_cell_measurement_theta_min      12
_cell_volume                     1094.2(3)
_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, 1999)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      298(2)
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_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  0.0239
_diffrn_reflns_av_sigmaI/netI    0.0228
_diffrn_reflns_limit_h_max       14
_diffrn_reflns_limit_h_min       -14
_diffrn_reflns_limit_k_max       14
_diffrn_reflns_limit_k_min       -1
_diffrn_reflns_limit_l_max       3
_diffrn_reflns_limit_l_min       -13
_diffrn_reflns_number            2162
_diffrn_reflns_theta_full        28.97
_diffrn_reflns_theta_max         28.97
_diffrn_reflns_theta_min         2.76
_diffrn_standards_decay_%        0.9
_diffrn_standards_interval_time  120
_diffrn_standards_number         2
_exptl_absorpt_coefficient_mu    7.806
_exptl_absorpt_correction_T_max  0.45
_exptl_absorpt_correction_T_min  0.24
_exptl_absorpt_correction_type   psi-scan
_exptl_absorpt_process_details   '(North <i>et al.</i>,  1968)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    4.294
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prism
_exptl_crystal_F_000             1302
_exptl_crystal_size_max          0.20
_exptl_crystal_size_mid          0.14
_exptl_crystal_size_min          0.10
_refine_diff_density_max         0.899
_refine_diff_density_min         -1.638
_refine_ls_extinction_coef       0.0031(2)
_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   1.129
_refine_ls_matrix_type           full
_refine_ls_number_parameters     68
_refine_ls_number_reflns         803
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.129
_refine_ls_R_factor_all          0.0262
_refine_ls_R_factor_gt           0.0238
_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^)+(0.0323P)^2^+10.2211P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0659
_refine_ls_wR_factor_ref         0.0669
_reflns_number_gt                751
_reflns_number_total             803
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            fj2116.cif
_cod_data_source_block           I
_cod_database_code               2218402
_cod_database_fobs_code          2218402