Na~2~Ca~3~Ta~2~O~9~ with a simple stacking of oxygen triangular nets
Yamane, Hisanori; Takahashi, Hiroki; Kajiwara, Takashi; Shimada, Masahiko; Acta Crystallographica Section C 55 (1999) 1978–1980; doi:10.1107/S0108270199010513

data_2009231
_publ_section_title
;
 Na~2~Ca~3~Ta~2~O~9~ with a simple stacking of oxygen triangular nets
;
_journal_issue                   12
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              1978
_journal_page_last               1980
_journal_paper_doi               10.1107/S0108270199010513
_journal_volume                  55
_journal_year                    1999
_chemical_formula_structural     'Na2 Ca3 Ta2 O9'
_chemical_formula_sum            'Ca3 Na2 O9 Ta2'
_chemical_formula_weight         672.12
_chemical_name_common            'sodium calcium tantalate'
_chemical_name_systematic
;
disodiumtricalciumditantalumnonaoxide
;
_space_group_IT_number           155
_symmetry_cell_setting           hexagonal
_symmetry_space_group_name_Hall  'R 3 2"'
_symmetry_space_group_name_H-M   'R 3 2 :H'
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                120.00
_cell_formula_units_Z            3
_cell_length_a                   5.6969(6)
_cell_length_b                   5.6969(6)
_cell_length_c                   23.523(3)
_cell_measurement_reflns_used    1199
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      27.49
_cell_measurement_theta_min      1.00
_cell_volume                     661.15(13)
_computing_cell_refinement       SMART
_computing_data_collection       'SMART (Bruker, 1997a)'
_computing_data_reduction        'XPREP (Bruker, 1997b)'
_computing_molecular_graphics    'ATOMS (Dowty, 1998)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 1997)'
_computing_structure_solution    'SIR92 (Altomare et al., 1994)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.991
_diffrn_measured_fraction_theta_max 0.991
_diffrn_measurement_device_type  'manufacturer?? CCD area detector'
_diffrn_measurement_method       '\w 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  0.069
_diffrn_reflns_av_sigmaI/netI    0.042
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_k_max       4
_diffrn_reflns_limit_k_min       -7
_diffrn_reflns_limit_l_max       27
_diffrn_reflns_limit_l_min       -30
_diffrn_reflns_number            1452
_diffrn_reflns_theta_full        27.49
_diffrn_reflns_theta_max         27.49
_diffrn_reflns_theta_min         2.60
_diffrn_standards_decay_%        0.14
_exptl_absorpt_coefficient_mu    26.678
_exptl_absorpt_correction_T_max  0.512
_exptl_absorpt_correction_T_min  0.071
_exptl_absorpt_correction_type   analytical
_exptl_absorpt_process_details   'face indexed'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    5.064
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       platelet
_exptl_crystal_F_000             900
_exptl_crystal_size_max          0.13
_exptl_crystal_size_mid          0.10
_exptl_crystal_size_min          0.03
_refine_diff_density_max         1.343
_refine_diff_density_min         -2.097
_refine_ls_abs_structure_details
'SHELXL97 (Sheldrick, 1997) (racemic twinning)'
_refine_ls_abs_structure_Flack   0.51(6)
_refine_ls_extinction_coef       0.0025(3)
_refine_ls_extinction_method     'SHELXL97 (Sheldrick, 1997)'
_refine_ls_goodness_of_fit_ref   1.187
_refine_ls_hydrogen_treatment    none
_refine_ls_matrix_type           full
_refine_ls_number_parameters     28
_refine_ls_number_reflns         348
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.187
_refine_ls_R_factor_all          0.022
_refine_ls_R_factor_gt           0.021
_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^)+(0.0095P)^2^+20.9824P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_ref         0.057
_reflns_number_gt                335
_reflns_number_total             348
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            br1255.cif
_cod_data_source_block           NCTO
_cod_original_sg_symbol_H-M      'R 3 2'
_cod_original_formula_sum        'Na2 Ca3 Ta2 O9'
_cod_database_code               2009231