Perovskite Blocks Research Articles

Influence of Mg2+ doping on the oxide ion conductivity of layered ferroelectric SrBi2Ta2O9

Layered perovskites structures are an interesting candidate to explore as a potential electrolyte materials for Solid oxide fuel cell (SOFC) applications. However, achieving a high ionic conductivity (∼0.01 S cm⁻1 below 650 °C) remains a significant challenge to lowering the SOFC operating temperatures. SrBi2Ta2O9 (SBT), an Aurivillius-based layered perovskite, is a well-known ferroelectric material with TC of 320 °C. Site exchange and Bi volatility related defects lead to ionic conductivity in SBT above 700 °C. Here, we aim to control the defect chemistry by doping to promote the oxygen vacancies. We show that Mg doping at the Ta-site in the perovskite block results in 4-fold increase in the bulk conductivity of SBT 3.65 × 10−4 S cm−1 and improvement in the ionic transport number from 0.26 to 0.71. The study provides an opportunity to design new oxide ion conductors in layered ferroelectric oxides.

A novel layered cobalt oxide Ba2Co9O14 as an efficient and durable bifunctional oxygen electrocatalyst for rechargeable zinc-air batteries

In this work, a layered cobalt oxide Ba2Co9O14 (BCO), belongs to a Ban+1ConO3n+3(Co8O8) family composed by alternating CdI2 based layers (Co8O8) with n (111) perovskite blocks (Ban+1ConO3n+3), has been developed as a potential bifunctional oxygen electrocatalyst candidate for efficient and durable rechargeable zinc-air battery (ZAB) application. Because of the greatly increased the specific surface area caused by ball-milling, the as-milled BCO material exhibits strongly enhanced bifunctional electrocatalytic activity towards oxygen reduction and oxygen evolution reaction in alkaline medium. Moreover, the assembled BCO-based ZAB yields an effectively improved maximum output power density of 166 mW cm−2, a considerable specific capacity of 789 mAh g−1, and excellent charge-discharge cycle stability of over 250 h at 10 mA cm−2 with over 1500 cycles.

Designing of phenothiazine dioxide based donor molecules with improved photovoltaic parameters for efficient perovskite solar cells

Perovskite solar cells are the emerging photovoltaics devices due to their high efficiency because of broad range light absorption and better charge carrier and separation properties. However, in the past few decades their material degradation and instability in the device operation accompanying low power conversion efficiency were the major drawbacks. To address these shortcomings, here we designed five Phenothiazine based novel hole-transporting molecules of d-Pi-A type with improved photovoltaic parameters for efficient perovskite solar devices. Detailed DFT calculation analysis with MPW1PW91 functions and 6–31 G basis set were performed for all molecules. Structural geometrical analysis along with density of states and transition density matrix analysis were extensively performed. Their electronic properties including HOMO and LUMO energies including energy gap, electron affinity, and ionization potential were also explored to elucidate the charge transfer characteristics. The lower values of reorganization in relation to reference molecules show that all designed molecules are better hole-transporters for perovskite building blocks. Lastly the devices photovoltaic parameter calculations for all the designed systems revealed that their Fill factor (FF), VOC and resultant power conversion efficiencies were significantly improved (18.63–22.81 % than its reference counterpart with PCE of 16.7 %) demonstrating their great potential for the future efficient PSCs devices.

Dielectric Properties and Magnetoelectric Effect of Bi7Fe3Ti3O21 Ceramic Material Doped with Gadolinium Ions

Pure Bi7Fe3Ti3O21 ceramic material and gadolinium ion (Gd3+)-doped ones were prepared by solid-state reaction method using simple oxides. The findings of the XRD measurements confirmed the initial author’s assumption that the dopant ions substituted in perovskite blocks influenced the dimensions of the unit cell parameters. All obtained materials are single-phase and show an orthorhombic structure with the Fm2m space group. Microstructure studies show that the admixture gadolinium doping changes the microstructure of the base material, changing grain shapes from plate-like to rounded. The temperature dependences of the electric permittivity have shown the existence of a maximum, the temperature location of which depends on both the frequency and the concentration of Gd3+ ions. The highest values of electric permittivity were characteristic of the material with an admixture of Gd3+ ions in the amount of x = 0.6 (f = 1 kHz), and the lowest values were for material with x = 0.2 (f = 1 kHz). Studies of the magnetoelectric effect have shown that the strongest coupling between magnetic and electrical properties was demonstrated by a material doped with Gd3+ ions in the amount of x = 0.2, for which the magnetoelectric coupling coefficient is equal to α = 12.58·10−9 s/m.

Effects of La doping on diffused ferroelectric phase transition, electric and dielectric properties of lead-free SrBi2Ta2O9 ceramics

Citric acid-assisted method was used to synthesize pure polycrystalline La-doped SrBi2Ta2O9 powders which were uniaxially pressed and sintered under different conditions. La doping of SrBi2Ta2O9 resulted in the shortening of Ta-O bond lengths, but increased the unit cell volume and decreased the crystallite size. The effect of sintering process on dielectric properties was studied in order to find optimal sintering conditions. Dielectric loss, measured at room temperature, increases when sintering temperature rises from 1100 to 1200?C, as well as when sintering time increases from 6 to 9 h. Thus, further investigation was performed on the sample sintered at 1100?C for 6 h. The obvious change in ?? around TC and diffusive phase transition, pronounced for the ceramics with higher La content, were characteristic of the doped ceramics. The diffused ferroelectric phase transition behaviour is caused by structural disorder at the Sr-sites (Sr, Bi and La cations) in the Bi2O2 layers and perovskite blocks. The electrical conductivity increases steadily at lower temperatures (below 200 ?C), but shows a strong temperature- and frequency-dependent trend at higher frequencies. La-doping decreases conductivity by hindering charge carriers? long-distance mobility.

Crystallization features and physical properties of the thin-film heterostructure of lead zirconate titanate – lead oxide

Various diagnostic techniques aimed at studying the structure and physical properties (synchronous thermal analysis, atomic force microscopy operating in the current measurement mode, electron-probe X-ray spectral microanalysis, dynamic method for determining the pyroelectric response) were used to study the crystallization features and physical properties of the thin-film heterostructure PZT – PbO1+x formed by a two-stage technique of RF magnetron sputtering of a ceramic target. During the first stage, amorphous films were deposited on a “cold” platinized silicon substrate, while the second stage involved high-temperature annealing in air. It was shown that annealing of amorphous films and crystallization of the intermediate pyrochlore phase are accompanied by additional oxidation of the structure resulting in the formation of lead orthoplumbate and lead dioxide and additional oxidation of organic inclusions. The presence of a liquid phase of lead oxide contributes to the formation of the pyrochlore phase. It was found that lead oxide layers have significantly higher through conductivity than perovskite blocks. It was assumed that the increased conductivity of lead oxide layers is associated with lead dioxide, which has high conductive properties. Self-polarized thin films were detected to have an abnormal electrical response to the strobing thermal exposure, including the typical pyroelectric response, local photoconductivity shunted by layers of the perovskite phase, and through photoconductivity. The presence of photoconductivity is also associated with the conductive properties of lead dioxide

Effect of isovalent substitution on structure of the two-slab BaNd2-xSmxIn2O7 indates

The conditions of isovalent substitution of Nd atoms for Sm atoms in A-positions of the BaNd2In2O7 two-slab perovskite-like structure of the BaNd2-xSmxIn2O7 type (0 £ x £ 1.8) have determined by X-ray powder diffraction methods. Tetragonal crystal structure (space group P42/mnm) of the BaNd2-xSmxIn2O7 phases with substitution degree of Nd atoms equal to 0.5, 1.0, 1.5 and 1.8 was determined by the Rietveld method. Crystal structure of BaNd2-xSmxIn2O7 is based on the two-dimensional (infinite in the XY plane) perovskite-like blocks, consisting of two slabs of the deformed InO6 octahedra connected by vertices. Ba atoms are localized only at 4f position inside the perovskite block, while REE atoms are placed only at 8j position at the boundary of the perovskite block. The adjacent perovskite-like blocks are separated by a slab of LnO9 polyhedra and held together by - O - Ln - O - interblock bonds. It is established that the isovalent substitution of Nd atoms by smaller Sm atoms leads to a decrease in the length of the Ln - O2 distance (from 0.230(2) nm to 0.206(2) nm) and to an increase in the degree of deformation of the interblocks of LnO9 polyhedra, the inner block polyhedra BaO12, and the InO6 octahedra as well. Such structural changes destabilize the interblock "stitching" and are one of the main destruction factors of the slab perovskite-like structure of the BaNd2-xSmxIn2O7 phases at x > 1.8. Data obtained could be used for directed regulation of structure-sensitive properties of materials based on the BaNd2In2O7 indate.

Antiferroelectric-like Behavior in a Lead-Free Perovskite Layered Structure Ceramic.

Antiferroelectric (AFE) materials have been intensively studied due to their potential uses in energy storage applications and energy conversion. These materials are characterized by double polarization-electric field (P-E) hysteresis loops and nonpolar crystal structures. Unusually, in the present work, Sr1.68La0.32Ta1.68Ti0.32O7 (STLT32), Sr1.64La0.36Ta1.64Ti0.36O7 (STLT36), and Sr1.85Ca0.15Ta2O7 (SCT15), lead-free perovskite layered structure (PLS) materials, are shown to exhibit AFE-like double P-E hysteresis loops despite maintaining a polar crystal structure. The double hysteresis loops are present over wide ranges of electric field and temperature. While neutron diffraction and piezoresponse force microscopy results indicate that the STLT32 system should be ferroelectric at room temperature, the observed AFE-like electrical behavior suggests that the electrical response is dominated by a weakly polar phase with a field-induced transition to a more strongly polar phase. Variable-temperature dielectric measurements suggest the presence of two-phase transitions in STLT32 at ca. 250 and 750 °C. The latter transition is confirmed by thermal analysis and is accompanied by structural changes in the layers, such as in the degree of octahedral tilting and changes in the perovskite block width and interlayer gap, associated with a change from non-centrosymmetric to centrosymmetric structures. The lower-temperature transition is more diffuse in nature but is evidenced by subtle changes in the lattice parameters. The dielectric properties of an STLT32 ceramic at microwave frequencies was measured using a coplanar waveguide transmission line and revealed stable permittivity from 1 kHz up to 20 GHz with low dielectric loss. This work represents the first observation of its kind in a PLS-type material.

Oxygen Ion and Proton Transport in Alkali-Earth Doped Layered Perovskites Based on BaLa2In2O7

Inorganic materials with layered perovskite structures have a wide range of physical and chemical properties. Layered perovskites based on BaLanInnO3n+1 (n = 1, 2) were recently investigated as protonic conductors. This work focused on the oxygen ion and proton transport (ionic conductivity and mobility) in alkali-earth (Sr2+, Ba2+)-doped layered perovskites based on BaLa2In2O7. It is shown that in the dry air conditions, the nature of conductivity is mixed oxygen–hole, despite the dopant nature. Doping leads to the increase in the conductivity values by up to ~1.5 orders of magnitude. The most proton-conductive BaLa1.7Ba0.3In2O6.85 and BaLa1.7Sr0.15In2O6.925 samples are characterized by the conductivity values 1.2·10−4 S/cm and 0.7·10−4 S/cm at 500 °C under wet air, respectively. The layered perovskites with Ruddlesden-Popper structure, containing two layers of perovskite blocks, are the prospective proton-conducting materials and further material science searches among this class of materials is relevant.

Combined effect of charge carriers and crystal structure on high-Tc superconductivity in codoped Y1-xCaxBa2-yLayCu3Oz

Polycrystalline samples of Y1-xCaxBa2-yLayCu3Oz cuprate superconductors with both x and y ranging from 0 to 0.5 were investigated. The combinative energy between the perovskite block and the rock-salt block in this codoped system was calculated according to a previously proposed “block model”. By defining a new parameter γ describing the combined effects of the combinative energy (lattice degree of freedom) and the charge carrier density (charge degree of freedom), it is revealed that the tendency of γ changing with doping is well consistent with that of the superconducting transition temperature (Tc) over the whole doping range, suggesting the important roles of both the lattice and charge degrees of freedom in influencing the unconventional superconductivity.

Origin of high piezoelectricity in CBT-based Aurivillius ferroelectrics: Glide of (Bi2O2)2+ blocks and suppressed internal bias field

This work investigates the substitution of Ce donor for Bi at A-site, which effectively improves the piezoelectricity and electrical resistivity of Aurivillius-phase CaBi4Ti4O15 (CBT) ceramic. Crystal structures of CaBi4-xCexTi4O15 ceramics are studied systematically, revealing the reason of unit cell contraction and the decreased ferro-distortion in crystal structure. The first-principles calculation shows that the enhancement of the intrinsic piezoelectricity in Ce-doped CBT ceramics come from the polarization stretching, where the translation and off-center displacement response under macroscopic strain of (Bi2O2)2+ layers playing an unexpectedly significant role. Ce doping can break the long-range ferroelectric chain, softening the flexibility of polarization and then making higher displacement response to strain for the other atoms, specially, the glide between the (Bi2O2)2+ layer and perovskite block is strong enhanced. Meanwhile, fewer defect dipoles (V″′Bi−VO••)dipolesin Ce-doped CBT ceramics result in a less internal bias field (Eib), which favors the polarization rotation and extension. Moreover, the significant role of oxygen vacancy ionization in electrical conductivity is inhibited, so both direct current resistance (ρdc) and activation energy of the charge carriers (Ea) are effectively enhanced in Ce-doped CBT ceramics.

Aurivillius Phase Bi4V3O12 with d1 Magnetic Cations, Anisotropic and Negative Thermal Expansion, Multiple Structural Transitions, and Low-Dimensional Magnetism.

Aurivillius phases are an important class of inorganic compounds as they often show ferroelectric properties, and some members of this family are used in nonvolatile ferroelectric memories. The majority of Aurivillius phases have nonmagnetic d0 cations in the perovskite block. Bi4Ti3O12 is the best-known and extensively studied compound within this family. Here, using a high-pressure, high-temperature synthesis method, we could successfully prepare a full magnetic analogue, Bi4V3O12, with d1 cations. Bi4V3O12 is unstable in air above about 520 K. However, in an inert atmosphere, Bi4V3O12 demonstrates two first-order reversible structural transitions near 525 and 760 K. The high-temperature prototypical phase is the same in both Bi4V3O12 and Bi4Ti3O12 with tetragonal (T) I4/mmm symmetry and aT = 3.85608(5) Å and cT = 32.6920(8) Å (at 850 K) for Bi4V3O12, while the low-temperature phases are different. Bi4V3O12 shows anisotropic thermal expansion above 300 K and negative volumetric thermal expansion above about 700 K. Magnetic measurements showed a broad maximum near 70 K on magnetic susceptibility, indicating the presence of low-dimensional magnetism with strong antiferromagnetic interactions between V4+ ions with the Curie-Weiss temperature of about -370 K. But no long-range magnetic ordering was found in Bi4V3O12 down to 2 K.

Understanding the piezoelectric origin of bismuth layer-structured ferroelectric polycrystal using first-principle method

Polycrystalline ferroelectric piezoelectric materials are widely used in various functional electronic devices. We present a systematic orientational average method to estimate the piezoelectric properties of ferroelectric polycrystals via first-principle calculations. This method can construct a bridge to connect the monocrystalline and polycrystalline ferroelectric piezoelectric materials, which opens a door to estimate the piezoelectric properties of polycrystals via first-principle calculations, helping the further study of piezoelectric polycrystals. The piezoelectric properties of bismuth layer-structured ferroelectrics (BLSFs) polycrystals are investigated via the method, which presents a good agreement in other theoretical and experimental results. It is found that the longitudinal polarization stretching and in-plane polarization rotation contribute the most of piezoelectricity for poled polycrystals. Unexpected polarization stretching of Bi2O2 layer and slipping between Bi2O2 layer and perovskite block are revealed, being considered to play an important role for the piezoelectricity of BLSFs.

Unique octahedral rotation pattern in the oxygen-deficient Ruddlesden-Popper compound Gd3Ba2Fe4O12.

A novel Ruddlesden-Popper-related compound, Gd3Ba2Fe4O12, was discovered and its crystal structure was determined via single-crystal X-ray diffraction. The structure has an ordered structure of octahedra and pyramids along the c axis. Gd3Ba2Fe4O12 belongs to the tetragonal system P42/ncm, with a = 5.59040 (10) Å and c = 35.1899 (10) Å. The A-site ions in the Ruddlesden-Popper structure, i.e. Gd3+ and Ba2+, exhibit an ordering along the c axis. The perfect oxygen deficiency is accommodated at the GdO layers in the proper Ruddlesden-Popper structure. Using the bond-valence-sum method, the Fe ions in the FeO6 octahedra and FeO5 pyramids represent valence states of +3 and +2.5, respectively, demonstrating a two-dimensional charge disproportionation. The corner-sharing FeO6 octahedra and FeO5 pyramids are tilted in opposite directions, with the neighbours around one axis of the simple perovskite configuration, which, using Glazer's notation, can be represented as a-b0c0/b0a-c0. In the perovskite blocks, the facing FeO5 pyramids across the Gd layer rotate in the same sense, which is a unique rotation feature related to oxygen deficiency.

Layered Perovskite Oxyiodide with Narrow Band Gap and Long Lifetime Carriers for Water Splitting Photocatalysis.

The development of semiconductors with narrow band gap and high stability is crucial for achieving solar to chemical energy conversion. Compounds with iodine, which has a high polarizability, have attracted attention because of their narrow band gap and long carrier lifetime, as typified by halide perovskite solar cells; however, they have been regarded as unsuitable for harsh photocatalytic water splitting because iodine is prone to self-oxidation. Here, we demonstrate that Ba2Bi3Nb2O11I, a layered Sillén-Aurivillius oxyiodide, not only has access to a wider range of visible light than its chloride and bromide counterparts, but also functions as a stable photocatalyst, efficiently oxidizing water. Density functional theory calculations reveal that the oxygen 2p orbitals in the perovskite block, rather than the fluorite Bi2O2 block as previously pointed out, anomalously push up the valence band maximum, which can be explained by a modified Madelung potential analysis that takes into account the high polarizability of iodine. In addition, the highly polarizable iodide contributes to longer carrier lifetime of Ba2Bi3Nb2O11I, allowing for a significantly higher quantum efficiency than its chloride and bromide counterparts. Visible-light-driven Z-scheme water splitting was achieved for the first time in an iodine-based system using Ba2Bi3Nb2O11I as an oxygen-evolution photocatalyst. The present study provides a novel approach for incorporating polarizable "soft" anions into building blocks of layered materials to manipulate the band structure and improve the carrier dynamics for visible-light responsive functions.

Tailoring c‐Axis Orientation in Epitaxial Ruddlesden–Popper Pr0.5Ca1.5MnO4 Films

AbstractInterest in layered Ruddlesden–Popper (RP) strongly correlated manganites of Pr0.5Ca1.5MnO4 as well as in their thin film polymorphs is motivated by the high temperature of charge orbital ordering above room temperature. The c‐axis orientation in epitaxial films is tailored by different SrTiO3 (STO) substrate orientations and CaMnO3 (CMO) buffer layers. Films on STO(110) show in‐plane alignment of the c‐axis parallel to the [100] direction. On STO(100), two possible directions of the in‐plane c‐axis lead to a mosaic like, quasi 2D nanostructure, consisting of RP, rock‐salt, and perovskite blocks. With the CMO buffer layer, Pr0.5Ca1.5MnO4 epitaxial films with c‐axis out‐of‐plane are realized. Different physical vapor deposition techniques as ion beam sputtering, pulsed laser deposition and metalorganic aerosol deposition are applied in order to distinguish effects of growth conditions from intrinsic epitaxial properties. Despite their very different growth conditions, surface morphology, crystal structure, and orientation of the thin films reveal a high level of similarity as verified by X‐ray diffraction, scanning, and high resolution transmission electron microscopy. For different epitaxial relations stress in the films is relaxed by means of modified interface chemistry. The charge ordering in the films occurs at a temperature close to that expected in bulk material.

Structural and physical properties of trilayer nickelates R4Ni3O10 ( R=La , Pr, and Nd)

We investigate the low temperature structural and physical properties of the trilayer nickelates R4Ni3O10 (R = La, Pr and Nd) using resistivity, thermopower, thermal conductivity, specific heat, high-resolution synchrotron powder X-ray diffraction and thermal expansion experiments. We show that all three compounds crystallize with a monoclinic symmetry, and undergo a metal-to-metal (MMT) transition at 135 K (La), 156 K (Pr) and 160 K (Nd). At MMT, the lattice parameters show distinct anomalies; however, without any lowering of the lattice symmetry. Unambiguous signatures of MMT are also seen in magnetic and thermal measurements, which suggest a strong coupling between the electronic, magnetic and structural degrees of freedom in these nickelates. Analysis of thermal expansion yields hydrostatic pressure dependence of MMT in close agreement with experiments. We show that the 9-fold coordinated Pr ions in the rocksalt (RS) layers have a crystal field (CF) split doublet ground state with possible antiferromagnetic ordering at 5 K. The Pr ions located in the perovskite block (PB) layers with 12-fold coordination, however, exhibit a non-magnetic singlet ground state. The CF ground state of Nd in both RS and PB layers is a Kramers doublet. Heat capacity of R = Nd shows a Schottky-like anomaly near35 K, and an upturn below T = 10 K suggesting the presence of short-range correlations between the Nd moments. However, no signs of long-range ordering could be found down to 2 K despite a sizeable theta_p ~ -40 K. The strongly suppressed magnetic long-range ordering in both R = Pr and Nd suggests the presence of strong magnetic frustration in these compounds. The low-temperature resistivity shows a T^0.5 dependence. No evidence for the heavy fermion behavior could be found in any of the three compounds.

Partial cationic order at the B site of the n = 3 Ruddlesden-Popper phases LaSr3(Fe,Co,Ga)3O10-δ studied by Neutron Powder Diffraction and X-ray Absorption Spectroscopy

The crystal chemistry of the Ruddlesden-Popper phases LaSr3Fe1.5Co1.5O10-δ, LaSr3Fe1.35Co1.35Ga0.3O10−δ, LaSr3Fe1.8Co0.6Ga0.6O10−δ and LaSr3Fe2.4Ga0.6O10−δ with tetragonal symmetry has been studied by Neutron Powder Diffraction (NPD) and X-ray Absorption Spectroscopy (XAS) varying Fe, Co and Ga content. NPD data shows that oxygen vacancies are located at the O(2) and O(4) crystal sites at the central octahedra of the perovskite block. Furthermore, Fe, Co and Ga cations are not homogeneously distributed, showing certain preference for particular crystal sites in the perovskite block. For instance, Fe cations tend to accommodate in sites with a lower concentration of oxygen defects, i.e. the B(2) crystal sites of the perovskite layers next to the rock salt layer, while Ga cations noticeably prefer the B(1) sites at the central perovskite layer. This cationic distribution was confirmed by Extended X-ray Absorption Fine Structure (EXAFS) analysis, which shows the average coordination number of Fe is always higher than the coordination number obtained for Co and Ga, in agreement with the preferential location of the oxygen vacancies at the central perovskite layer where Ga cations are located according to NPD data. The combination of NPD and XAS data was found effective to describe the crystal chemistry and defect structure of the LaSr3FexCoyGa3−x−yO10−δ system.

Synthesis and characterisation of Sr4Fe3-xCrxO10-δ: Stabilisation of n=3 Ruddlesden-Popper phases through Cr doping

Ruddlesden-Popper type compounds have the general formula, An+1MnO3n+1±x (typically A is a rare earth, alkaline earth, M is a transition metal), and are constructed of perovskite-type layers separated by rock salt type blocks. While n ​= ​1, 2 phases are typically straightforward to prepare, the synthesis of higher order (n ​> ​2) systems is difficult. In this paper we show that chromate (CrO42−) doping can be exploited to stabilise new n ​= ​3 Ruddlesden-Popper systems, Sr4Fe3-xCrxO10-δ: without chromate doping, a mixture of the n ​= ​2 phase Sr3Fe2O7-x and perovskite-type SrFeO3-x is obtained. This can be explained by the stabilisation of the central perovskite building block by chromate incorporation, similar to prior work on sulfate and carbonate doping in this system. The structure, and Fe/Cr oxidation states were evaluated by X-ray diffraction, 57Fe Mössbauer spectroscopy and X-ray absorption spectroscopy supporting the incorporation of Cr as CrO42−. In order to examine the potential of these new systems for use as a SOFC cathode material, conductivity studies were carried out, which showed semiconducting behaviour with slightly higher conductivities than the sulfate doped counterparts.

Synthesis and thermal stability studies of mixed A-site Dion-Jacobson triple-layered perovskites,A′LaNaNb3O10 (A′ = H, Li, Na, K, Rb, CuCl)

The new mixed-metal Dion-Jacobson layered perovskite RbLaNaNb3O10 has been prepared by direct reaction. Rietveld refinement of X-ray diffraction data shows this compound to be tetragonal (a ​= ​3.88703(7) Å, c ​= ​15.1349(5) Å; S.G. P4/mmm) and isostructural to RbCa2Nb3O10 with La and Na statistically distributed over the A-site within the perovskite block. The compound can be topochemically manipulated, readily undergoing ion exchange reactions to produce the series A′LaNaNb3O10 (A′ ​= ​H, Li, Na, K, CuCl). Thermal studies show that, with the exception of KLaNaNb3O10, the exchange products are all low temperature phases, decomposing below 800 ​°C with a decomposition pathway varying with the nature of the interlayer species. Significant to this study is the observation that the rare combination of site sharing trivalent and monovalent cations (La/Na) imparts an increased stability for the A′LaNaNb3O10 compounds relative to the corresponding A′Ca2Nb3O10 analogues – the thermal stability in LiLaNaNb3O10 for example is over 50 ​°C higher than that of LiCa2Nb3O10.