Long-Range-Ordered Coexistence of 4-, 5-, and 6-Coordinate Niobium in the Mixed Ionic-Electronic Conductor γ-Ba4Nb2O9
Dunstan, Matthew T.; Blanc, Frédéric; Avdeev, Maxim; McIntyre, Garry J.; Grey, Clare P.; Ling, Chris D.; Chemistry of Materials 25 (2013) 3154–; doi:10.1021/cm4014656

data_4001799
_publ_section_title
;
 Long-Range-Ordered Coexistence of 4-, 5-, and 6-Coordinate Niobium in the
 Mixed Ionic-Electronic Conductor \g-Ba4Nb2O9
;
_journal_issue                   15
_journal_name_full               'Chemistry of Materials'
_journal_page_first              3154
_journal_paper_doi               10.1021/cm4014656
_journal_volume                  25
_journal_year                    2013
_chemical_formula_sum            'Ba4 Nb2 O9'
_chemical_formula_weight         879.2
_chemical_name_systematic        ' ?'
_space_group_IT_number           29
_symmetry_cell_setting           orthorhombic
_symmetry_Int_Tables_number      29
_symmetry_space_group_name_Hall  'P 2c -2ac'
_symmetry_space_group_name_H-M   'P c a 21'
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            24
_cell_length_a                   12.0872(7)
_cell_length_b                   24.8979(8)
_cell_length_c                   21.0015(10)
_cell_measurement_reflns_used    3461
_cell_measurement_temperature    293
_cell_measurement_theta_max      ??
_cell_measurement_theta_min      2
_cell_volume                     6320.3(5)
_computing_cell_refinement       RAFD19
_computing_data_collection       MAD
_computing_data_reduction        'RETREAT (Wilkinson et al., 1988)'
_computing_structure_refinement  'Jana2006 Version : 04/09/2012'
_diffrn_ambient_temperature      295
_diffrn_detector                 '3He multi-wire proportional counter'
_diffrn_detector_area_resol_mean '0.2 degrees'
_diffrn_measured_fraction_theta_full 0.91
_diffrn_measured_fraction_theta_max 0.7
_diffrn_measurement_device       D19
_diffrn_measurement_device_type  'Area detector based neutron diffractometer'
_diffrn_measurement_method       'omega scans'
_diffrn_measurement_specimen_support 'Ti pin'
_diffrn_radiation_monochromator  germanium
_diffrn_radiation_probe          neutron
_diffrn_radiation_source         'Institut Laue-Langevin'
_diffrn_radiation_type           Neutron
_diffrn_radiation_wavelength     1.2467
_diffrn_reflns_av_R_equivalents  0.0644
_diffrn_reflns_av_sigmaI/netI    0.0202
_diffrn_reflns_limit_h_max       11
_diffrn_reflns_limit_h_min       -14
_diffrn_reflns_limit_k_max       24
_diffrn_reflns_limit_k_min       -35
_diffrn_reflns_limit_l_max       27
_diffrn_reflns_limit_l_min       -26
_diffrn_reflns_number            27184
_diffrn_reflns_reduction_process
'3D minimum sigma(I)/I (Wilkinson et al., 1988)'
_diffrn_reflns_theta_full        26.06
_diffrn_reflns_theta_max         61.31
_diffrn_reflns_theta_min         2.87
_diffrn_standards_decay_%        0
_diffrn_standards_interval_count 'after every 82 degree omega scan'
_diffrn_standards_number         294
_exptl_absorpt_coefficient_mu    0.002
_exptl_crystal_density_diffrn    5.5418
_exptl_crystal_F_000             9072
_refine_diff_density_max         5.57
_refine_diff_density_min         -4.12
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_gt    3.75
_refine_ls_goodness_of_fit_ref   3.48
_refine_ls_number_constraints    1
_refine_ls_number_parameters     813
_refine_ls_number_reflns         10365
_refine_ls_number_restraints     0
_refine_ls_R_factor_all          0.0822
_refine_ls_R_factor_gt           0.0669
_refine_ls_shift/su_max          0.0411
_refine_ls_shift/su_mean         0.0091
_refine_ls_structure_factor_coef F
_refine_ls_weighting_details     w=1/(\s^2^(F)+0.0001F^2^)
_refine_ls_weighting_scheme      sigma
_refine_ls_wR_factor_gt          0.0683
_refine_ls_wR_factor_ref         0.0696
_reflns_number_gt                8745
_reflns_number_total             10365
_reflns_threshold_expression     I>3\s(I)
_cod_data_source_file            cm4014656_si_002.cif
_cod_data_source_block           I
_cod_original_sg_symbol_Hall     'P -2xac;-2ya;2zc'
_cod_database_code               4001799