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oai:figshare.com:article/33741889 2026-09-14T13:59:52Z portal_1197 item_type_3 month_year_09_2026

Data for Structural Disorder in (Bi, M)2(Fe, Mn, Bi)2O6+x (M = Na or K) Pyrochlores Seen from Reverse Monte Carlo Analysis of Neutron Total Scattering Richard I. Walton (1328463) Chemistry, Physical and theoretical Monte Carlo method Niobium Migrated from ePrints The average structures of the polycrystalline pyrochlores (Na0.60Bi1.40)(Fe1.06Mn0.17Bi0.77)O6.87 and (K0.24Bi1.51)(Fe1.07Mn0.15Bi0.78)O6.86 can be refined through Rietveld refinement against Bragg scattering data using cubic space group Fd3 ̅m, with off-centred 96h and 32e positions describing the A2Oʹ network. Investigation of their local structures through neutron total scattering confirms the extent of disorder within these materials, and furthermore shows significant deviation from the average structure, which is not accounted for through analysis of Bragg data alone. Reverse Monte Carlo (RMC) analysis with a 6 × 6 × 6 supercell was used to model accurately this local disorder, revealing ellipsoidal distributions for A-site potassium, distinctly different to the hollow torus-shaped distributions for the sodium and bismuth cations. It is shown through bond valence sum analysis that whilst these atomic displacements allow for the steric preferences of Bi3+, they are also necessary to satisfy the valence of both the bismuth and the alkali metals on the A sites. Analysis of the final RMC configuration showed the BO6 octahedra for the separate B site metals to be more regular (O–B–O ≈ 90°) than those in the Rietveld model (O–B–O ≈ 85/95°) which describes an average of the three different environments.<br><br>Two ascii files are present that contain the pair distribution functions for the K-pyrochlore and Na-pyrochlore. 2017-07-27T00:00:00Z Dataset Dataset 10.82444/warw.33741889.v1 https://figshare.com/articles/dataset/Data_for_Structural_Disorder_in_Bi_M_2_Fe_Mn_Bi_2O6_x_M_Na_or_K_Pyrochlores_Seen_from_Reverse_Monte_Carlo_Analysis_of_Neutron_Total_Scattering/33741889 CC BY 4.0