NaCa~1.5~(NbO)~2~O~2~(AsO~4~)~2~
Ben Amor, Rym; Zid, Mohamed Faouzi; Acta Crystallographica, Section E 61 (2005) i228–i230; doi:10.1107/S1600536805031429

data_2207204
_publ_section_title
;
NaCa~1.5~(NbO)~2~O~2~(AsO~4~)~2~
;
_journal_coeditor_code           DN6243
_journal_issue                   11
_journal_name_full               'Acta Crystallographica, Section E'
_journal_page_first              i228
_journal_page_last               i230
_journal_paper_doi               10.1107/S1600536805031429
_journal_volume                  61
_journal_year                    2005
_chemical_formula_iupac          'Na Ca1.5 (NbO)2 O2 (As O4)2'
_chemical_formula_moiety         'As Nb O6, 0.435(Ca), 0.315(Ca), 0.5(Na)'
_chemical_formula_structural     'Na Ca1.5 (NbO)2 O2 (As O4)2'
_chemical_formula_sum            'As2 Ca1.5 Na Nb2 O12'
_chemical_formula_weight         610.78
_chemical_name_systematic
;
sodium calcium niobate oxide arsenate
;
_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                 113.8270(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   6.730(2)
_cell_length_b                   22.302(3)
_cell_length_c                   7.4309(9)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    298(2)
_cell_measurement_theta_max      14
_cell_measurement_theta_min      12
_cell_volume                     1020.3(4)
_computing_cell_refinement       'CAD-4 EXPRESS'
_computing_data_collection
;
CAD-4 EXPRESS (Duisenberg, 1992; Mac\'i\<cek & Yordanov, 1992;
Enraf--Nonius, 1994)
;
_computing_data_reduction        'XCAD4 (Harms & Wocadlo, 1995)'
_computing_molecular_graphics
;
DIAMOND (Brandenburg, 1998), ORTEPIII (Burnett & Johnson, 1996) and
ORTEP-3 for Windows (Farrugia, 1997)
;
_computing_publication_material  SHELXL97
_computing_structure_refinement  'SHELXL97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      298(2)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_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  0.0152
_diffrn_reflns_av_sigmaI/netI    0.0250
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -8
_diffrn_reflns_limit_k_max       31
_diffrn_reflns_limit_k_min       -1
_diffrn_reflns_limit_l_max       1
_diffrn_reflns_limit_l_min       -10
_diffrn_reflns_number            1683
_diffrn_reflns_theta_full        29.96
_diffrn_reflns_theta_max         29.96
_diffrn_reflns_theta_min         3.43
_diffrn_standards_decay_%        1.2
_diffrn_standards_interval_time  120
_diffrn_standards_number         2
_exptl_absorpt_coefficient_mu    9.544
_exptl_absorpt_correction_T_max  0.3857
_exptl_absorpt_correction_T_min  0.2605
_exptl_absorpt_correction_type   psi-scan
_exptl_absorpt_process_details   '(North et al., 1968)'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    3.977
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prisme
_exptl_crystal_F_000             1140
_exptl_crystal_size_max          0.16
_exptl_crystal_size_mid          0.12
_exptl_crystal_size_min          0.10
_refine_diff_density_max         0.653
_refine_diff_density_min         -0.745
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.101
_refine_ls_hydrogen_treatment    undef
_refine_ls_matrix_type           full
_refine_ls_number_parameters     91
_refine_ls_number_reflns         1495
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.101
_refine_ls_R_factor_all          0.0245
_refine_ls_R_factor_gt           0.0194
_refine_ls_shift/su_max          0.021
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w = 1/[\s^2^(Fo^2^)+(0.0195P)^2^+2.343P] where P = (Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0500
_refine_ls_wR_factor_ref         0.0514
_reflns_number_gt                1337
_reflns_number_total             1495
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            dn6243.cif
_cod_original_sg_symbol_H-M      'C 2/c'
_cod_original_formula_sum        'As2 Ca1.5 Na1 Nb2 O12'
_cod_database_code               2207204