Structural evolution of Na0.5K0.5NbO3 at high temperatures
Ishizawa, Nobuo; Wang, Jun; Sakakura, Terutoshi; Inagaki, Yumi; Kakimoto, Ken-ichi; Journal of Solid State Chemistry 183 (2010) 2731–2738; doi:10.1016/j.jssc.2010.09.018

data_1563426
_publ_section_title
;
 Structural evolution of Na0.5K0.5NbO3 at high temperatures
;
_journal_issue                   11
_journal_name_full               'Journal of Solid State Chemistry'
_journal_page_first              2731
_journal_page_last               2738
_journal_paper_doi               10.1016/j.jssc.2010.09.018
_journal_volume                  183
_journal_year                    2010
_chemical_formula_sum            'K0.5 Na0.5 Nb O3'
_chemical_formula_weight         171.96
_space_group_IT_number           38
_space_group_name_Hall           'B 2 -2'
_space_group_name_H-M_alt        'B m m 2'
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_H-M   'B m m 2'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            2
_cell_length_a                   5.6573(2)
_cell_length_b                   3.95510(10)
_cell_length_c                   5.6717(2)
_cell_measurement_temperature    295
_cell_volume                     126.905(7)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      295
_diffrn_measured_fraction_theta_full 0.913
_diffrn_measured_fraction_theta_max 0.913
_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  0.0138
_diffrn_reflns_av_sigmaI/netI    0.0202
_diffrn_reflns_limit_h_max       10
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       7
_diffrn_reflns_limit_k_min       -7
_diffrn_reflns_limit_l_max       10
_diffrn_reflns_limit_l_min       -5
_diffrn_reflns_number            658
_diffrn_reflns_theta_full        40.20
_diffrn_reflns_theta_max         40.20
_diffrn_reflns_theta_min         5.09
_exptl_absorpt_coefficient_mu    5.375
_exptl_crystal_density_diffrn    4.500
_exptl_crystal_density_method    'not measured'
_exptl_crystal_F_000             160
_refine_diff_density_max         1.638
_refine_diff_density_min         -1.572
_refine_diff_density_rms         0.231
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.00
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.139
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     16
_refine_ls_number_reflns         298
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.139
_refine_ls_R_factor_all          0.0213
_refine_ls_R_factor_gt           0.0213
_refine_ls_shift/su_max          0.040
_refine_ls_shift/su_mean         0.005
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0394P)^2^+0.1524P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0543
_refine_ls_wR_factor_ref         0.0543
_reflns_number_gt                298
_reflns_number_total             298
_reflns_threshold_expression     >2\s(I)
_cod_data_source_file            100912_NKN_all.cif
_cod_data_source_block           d1_295K
_cod_original_formula_sum        'K0.50 Na0.50 Nb O3'
_cod_database_code               1563426