High-resolution Synchrotron X-ray Diffraction Data Research Articles

Resilience of the Aurivillius structure upon La and Cr doping in a Bi5Ti3FeO15 multiferroic.

Combining the experimental techniques of high-resolution X-ray diffraction, magnetometry, specific heat measurement, and X-ray photoelectron, Raman and dielectric spectroscopy techniques, we have studied the influence of La and Cr doping on the crystal structure and magnetism of the room temperature Aurivillius multiferroic Bi5Ti3FeO15 by investigating the physical properties of (Bi4La)Ti3FeO15 and Bi5Ti3 (Fe0.5Cr0.5)O15. The parent (Bi5Ti3FeO15) and the doped ((Bi4La)Ti3FeO15 and Bi5Ti3(Fe0.5Cr0.5)O15) compounds crystallize in the A21am space group, which is confirmed through our analysis of high-resolution synchrotron X-ray diffraction data obtained on phase-pure polycrystalline powders. We determined the oxidation states of the metal atoms in the studied compounds as Fe3+, Ti4+, Cr3+, and La3+ through the analysis of X-ray photoelectron spectroscopy data. The magnetic susceptibilities of the three compounds are marked by the absence of a long-range ordered ground state, but dominated by superparamagnetic clusters with dominant antiferromagnetic interactions. This signature of short-range magnetism is also seen in specific heat as a low temperature enhancement which is suppressed upon the application of external magnetic fields up to 8 T. Our dielectric spectroscopy experiments showed that the three studied compounds display similar features in the dielectric constant measured as a function of frequency. However, upon doping La at the Bi site, the width of the ferroelectric hysteresis loop increases for (Bi4La)Ti3FeO15 compared to that of the parent compound Bi5Ti3FeO15, and with Cr doping, Bi5Ti3(Fe0.5Cr0.5)O15 becomes a leaky dielectric. The resilience of the Aurivillius crystal structure towards doping of La at the Bi site and Cr at the Fe site is clearly seen in the bulk properties of magnetic susceptibility, specific heat and the average crystal structure. The relevance of changes in the local structure is evident from our Raman spectroscopy and X-ray pair distribution function studies.

Multiple unconventional charge density wave transitions in LaPt2Si2 superconductor clarified with high-energy X-ray diffraction

The quasi-2D platinum-based rare earth intermetallic LaPt2Si2 has attracted attention as it exhibits strong interplay between charge density wave order and superconductivity. However, most of the results reported on this material come from theoretical calculations, preliminary bulk investigations and powder samples, which makes it difficult to uniquely determine the temperature evolution of its crystal structure and, consequently, of its charge density wave transition. Therefore, the published literature around LaPt2Si2 is often controversial. Here, by means of high-resolution synchrotron X-ray diffraction data, we clarify some of the poorly or partially understood aspects of the physics of LaPt2Si2. In particular, we resolve the complex evolution of its crystal structure and superstructures, identifying the temperature dependence of multiple density wave transitions in good quality LaPt2Si2 single crystals. According to our findings, on cooling from room temperature LaPt2Si2 undergoes a series of subtle structural transitions which can be summarised as follows: second order commensurate tetragonal (P4/nmm)-to-incommensurate structure followed by a first order incommensurate-to-commensurate orthorhombic (Pmmn) transition and then a first order commensurate orthorhombic (Pmmn)-to-commensurate tetragonal (P4/nmm). The structural transitions are accompanied by both incommensurate and commensurate superstructural distortions of the lattice. The observed behavior is compatible with discommensuration of the CDW in this material.

Antisite disorder and Berry curvature driven anomalous Hall effect in the spin gapless semiconducting Mn2CoAl Heusler compound

Spin gapless semiconductors exhibit a finite band gap for one spin channel and a closed gap for another spin channel, and they have emerged as a new state of magnetic materials with a great potential for spintronic applications. The first experimental evidence for spin gapless semiconducting behavior was observed in an inverse Heusler compound ${\mathrm{Mn}}_{2}\mathrm{CoAl}$. Here, we report a detailed investigation of the crystal structure and anomalous Hall effect in ${\mathrm{Mn}}_{2}\mathrm{CoAl}$ using experimental and theoretical studies. The analysis of the high-resolution synchrotron x-ray diffraction data shows antisite disorder between Mn and Al atoms within the inverse Heusler structure. The temperature-dependent resistivity shows semiconducting behavior and follows Mooij's criteria for disordered metal. The scaling behavior of the anomalous Hall resistivity suggests that the anomalous Hall effect in ${\mathrm{Mn}}_{2}\mathrm{CoAl}$ is primarily governed by an intrinsic mechanism due to the Berry curvature in momentum space. The experimental intrinsic anomalous Hall conductivity (AHC) is found to be $\ensuremath{\sim}35$ S/cm, which is considerably larger than the theoretically predicted value for ordered ${\mathrm{Mn}}_{2}\mathrm{CoAl}$. Our first-principles calculations conclude that the antisite disorder between Mn and Al atoms enhances the Berry curvature and hence the value of intrinsic AHC, which is in very good agreement with the experiment.

Atomic disorder and Berry phase driven anomalous Hall effect in a Co2FeAl Heusler compound

${\mathrm{Co}}_{2}$-based Heusler compounds are promising materials for spintronics applications due to their high Curie temperature, large spin polarization, large magnetization density, and exotic transport properties. In the present paper, we report the anomalous Hall effect (AHE) in a polycrystalline ${\mathrm{Co}}_{2}\mathrm{FeAl}$ Heusler compound using combined experimental and theoretical studies. The Rietveld analysis of high-resolution synchrotron x-ray diffraction data reveals a large degree $(\ensuremath{\sim}50%)$ of antisite disorder between Fe and Al atoms. The analysis of anomalous transport data provides the experimental anomalous Hall conductivity (AHC) about 227 S/cm at 2 K with an intrinsic contribution of 155 S/cm, which has nearly constant variation with temperature. The detailed scaling analysis of anomalous Hall resistivity suggests that the AHE in ${\mathrm{Co}}_{2}\mathrm{FeAl}$ is governed by the Berry phase driven intrinsic mechanism. Our theoretical calculations reveal that the disorder present in the ${\mathrm{Co}}_{2}\mathrm{FeAl}$ compound enhances the Berry curvature induced intrinsic AHC.

Phase Analysis of Australian Uranium Ore Concentrates Determined by Variable Temperature Synchrotron Powder X-ray Diffraction.

The chemical speciation of uranium oxides is sensitive to the provenance of the samples and their storage conditions. Here, we use diffraction methods to characterize the phases found in three aged (>10 years) uranium ore concentrates of different origins as well as in situ analysis of the thermally induced structural transitions of these materials. The structures of the crystalline phases found in the three samples have been refined, using high-resolution synchrotron X-ray diffraction data. Rietveld analysis of the samples from the Olympic Dam and Ranger uranium mines has revealed the presence of crystalline α-UO2(OH)2, together with metaschoepite (UO2)4O(OH)6·5H2O, in the aged U3O8 samples, and it is speculated that this forms as a consequence of the corrosion of U3O8 in the presence of metaschoepite. The third sample, from the Beverley uranium mine, contains the peroxide [UO2(η2-O2)(H2O)2] (metastudtite) together with α-UO2(OH)2 and metaschoepite. A core-shell model is proposed to account for the broadening of the diffraction peaks of the U3O8 evident in the samples.

Tunnel structure of tetragonal tungsten bronzes BaTa2O6, Ba0.8Ta2O5.8, and Ba0.5Ta2O5.5 studied using synchrotron X-ray and neutron diffraction

The complex oxide system of Ba-Ta-O presents interesting cases of tetragonal tungsten bronze (TTB) phases being formed over a wide compositional range of Ba1−xTa2O6−x, 0 ≤ x ≤ 0.65 [X. Kuang et al., Inorg. Chem., 2013, 52, 13244−13252]. Compared to the common formalism of the TTB phase AB2O6, Ba1−xTa2O6−x is highly off stoichiometric and is presumed to involve substantial structural modifications. In this study, Ba1−xTa2O6−x samples were prepared with the chemical compositions of BaTa2O6 (x = 0), Ba0.8Ta2O5.8 (x = 0.2), and Ba0.5Ta2O5.5 (x = 0.5). Rietveld refinement and Fourier electron density calculation, using high-resolution synchrotron X-ray diffraction data, revealed that the above three compositions have distinct local structural features, and the irregularity escalates with the increase of x. In all the three compositions, the Ba position inside the pentagonal tunnel (A2 site) was lightly split, reflecting the oversize polyhedral cavity. Additionally, Ba0.8Ta2O5.8 and Ba0.5Ta2O5.5 contained segments of (TaO)3+ chains in the pentagonal tunnel and Ta5+ in the triangular tunnel (A3 site). Hence, the unit cell structure of BaTa2O6, Ba0.8Ta2O5.8, and Ba0.5Ta2O5.5 can be represented as Ba5[Ta10O30], Ba4.26(TaO)0.04Ta0.22[Ta10O30], and Ba2.84(TaO)1.19Ta0.18[Ta10O30], respectively. Dielectric constants (κ) of Ba1−xTa2O6−x were measured in the temperature range of 30–450 K and at frequencies of 100 kHz−1 MHz. Compared to BaTa2O6, which displayed high κ (≈100 at 300 K) and broad relaxation peaks below 50 K, Ba0.8Ta2O5.8 and Ba0.5Ta2O5.5 exhibited markedly reduced lattice polarizations.

Anomalous atomic displacement parameters and local dynamics in the Curie range of a Pb-free relaxor ferroelectric system (Bi1-xBax)(Fe1-xTix)O3(0.36 ≤ x ≤ 0.50)

We report here the relaxor ferroelectric (RFE) behaviour in a multiferroic solid solution system, (Bi1-xBax)(Fe1-xTix)O3, at a critical disorder level of xC ∼ 0.35 in BiFeO3 and 0.65 (i.e., 1-xC = 0.35) in BaTiO3 similar to the 1:2 ratio of Mg2+ and Nb5+ in the canonical RFE Pb(Mg1/3Nb2/3)O3. This Pb-free system, like canonical Pb-based RFEs, does not exhibit macroscopic symmetry breaking and shows only the signatures of ergodicity breaking at Vogel-Fulcher freezing temperature (TVF). The atomic displacement parameters (ADPs) of Fe3+/Ti4+ and O2−, obtained using high wave vector (Q) and high-resolution synchrotron x-ray diffraction data as a function of temperature, show anomalous diffuse peaks in the Curie range. It is shown that the diffuse peak in ADPs is due to softening of the vibrational frequencies of the B-O chain (B = Fe3+/Ti4+ and O = O2−) below the Burns temperature (TB) followed by hardening below the characteristic temperature (T′m), which corresponds to a peak in the dielectric permittivity (ε′).

Structural characterization of natural diamond shocked to 60 GPa; implications for Earth and planetary systems

The possible presence of the high-density carbon polymorph with hexagonal symmetry known as “lonsdaleite” provides an important marker for shock impact events. It is typically considered to form as a metastable phase produced from graphite or other carbonaceous precursors. However, its existence has recently been called into question. Here we collected high-resolution synchrotron X-ray diffraction data for laboratory-shocked and natural impact diamonds that both show evidence for deviations from cubic symmetry, that would be consistent with the appearance of hexagonal stacking sequences. These results show that hexagonality can be achieved by shocking diamond as well as from graphite precursors. The diffraction results are analyzed in terms of a general model that describes intermediate stacking sequences between pure diamond (fully cubic) and “lonsdaleite” (fully hexagonal) phases, with provision made for ordered vs disordered stacking arrangements. This approach provides a “hexagonality index” that can be used to characterize and distinguish among samples that have experienced different degrees of shock or static high pressure-high temperature treatments. We have also examined the relative energetics of diamond and “lonsdaleite” structures using density functional theoretical (DFT) methods. The results set limits on the conditions under which a transformation between diamond and “lonsdaleite” structures can be achieved. Calculated Raman spectra provide an indicator for the presence of extended hexagonal stacking sequences within natural and laboratory-prepared samples. Our results show that comparable crystallographic structures may be developed by impact-generated shockwaves starting from ambient conditions using either of the two different allotropes of carbon (diamond, graphite). This broadens the scope for its occurrence in terrestrial and planetary systems.

Selenides Based Sodium Superionic Conductors

All-solid-state Na-ion batteries that operate at or close to room temperature are a promising next-generation battery technology with enhanced safety and reduced manufacturing cost. An indispensable component of this technology is the solid state electrolyte that allows rapid shuttling of the mobile cation (i.e., Na+) between the cathode and anode. However, there are very few fast Na-ion conductors with ionic conductivity approaching that of the liquid counterparts (i.e., 1 mS cm-1). Compared to oxides and sulfides, selenides form a huge unexplored chemical space for fast ionic conductor discovery. Based upon ionic size considerations, selenide-based compounds may provide a more suitable structural framework for the rapid diffusion of the much larger Na+ cations compared with Li+. This consideration led us to an extensive search of fast Na-ion conductors in the Se-based chemical space via high-throughput computational screening, and has identified cubic Na3PSe4 as one of the most promising candidates. In this work, we present the synthesis and structural characterization of Na3PSxSe4-x (x = 0, 1, 2, 3, 4). The structures of these phases are determined from high-resolution synchrotron X-ray diffraction data, which allow us to unambiguously identify a tetragonal-to-cubic phase transition with increasing Se concentration in Na3PSxSe4-x. The Na-ion conductivity and activation energy for Na-ion diffusion were further characterized via variable temperature impedance spectroscopy, from which a negative correlation between the activation barrier and Se concentration can be established. Of particular note is that the x = 4 end member (i.e., cubic Na3PSe4) possesses a room-temperature ionic conductivity exceeding 0.1 mS cm-1, and does not require high temperature sintering to minimize grain boundary resistance, making it a promising solid-state electrolyte candidate for all-solid-state Na-ion battery applications. These experimental results were complemented by ab initio computation through which we demonstrate an intriguing interplay between the tetragonal-to-cubic phase transition, defect formation, and Na+ migration. This work has two important implications for future studies in related fields: (1) selenide based compounds represent a promising platform for the discovery of new fast Na-ion conductors; and (2) the current study opens up new opportunities for the exploration of Se and/or S based battery chemistry, such as the construction of all-solid-state Na/Se battery.

Probing Ultrafast Photoinduced Electron Transfer to TiO2 from CdS Nanocrystals of Varying Crystallographic Phase Content

The photoinduced electron transfer processes in a nanoheterostructured semiconductor assembly are complex and depend on various parameters of the constituents of the assembly. We present here the ultrafast electron transfer characteristics of an assembly comprised of a wide band semiconductor, titanium dioxide (TiO2), attached to light-harvesting cadmium sulfide (CdS) nanocrystals of varying crystallographic phase content. Quantitative analysis of synchrotron high-resolution X-ray diffraction data of CdS nanocrystals precisely reveals the presence of both wurtzite and zinc blende phases in varying amounts. The estimated content of crystal phases is observed to be strongly dependent on an important synthesis parameter, viz., the ratio of the two solvents. The biphasic nature of CdS influences directly the shape of the nanocrystal at long reaction times as well as the transfer of the photoexcited electrons from the CdS to TiO2 as obtained from transient absorption spectroscopy. A higher amount of zinc blend...

Crystal Structure and Catalytic Behavior in Olefin Epoxidation of a One-Dimensional Tungsten Oxide/Bipyridine Hybrid.

The tungsten oxide/2,2'-bipyridine hybrid material [WO3(2,2'-bpy)]·nH2O (n = 1-2) (1) has been prepared in near quantitative yield by the reaction of H2WO4, 2,2'-bpy, and H2O in the mole ratio of ca. 1:2:700 at 160 °C for 98 h in a rotating Teflon-lined digestion bomb. The solid-state structure of 1 was solved and refined through Rietveld analysis of high-resolution synchrotron X-ray diffraction data collected for the microcrystalline powder. The material, crystallizing in the orthorhombic space group Iba2, is composed of a one-dimensional organic-inorganic hybrid polymer, ∞(1)[WO3(2,2'-bpy)], topologically identical to that found in the previously reported anhydrous phases [MO3(2,2'-bpy)] (M = Mo, W). While in the latter the N,N'-chelated 2,2'-bpy ligands of adjacent corner-shared {MO4N2} octahedra are positioned on the same side of the 1D chain, in 1 the 2,2'-bpy ligands alternate above and below the chain. The catalytic behavior of compound 1 for the epoxidation of cis-cyclooctene was compared with that for several other tungsten- or molybdenum-based (pre)catalysts, including the hybrid polymer [MoO3(2,2'-bpy)]. While the latter exhibits superior performance when tert-butyl hydroperoxide (TBHP) is used as the oxidant, compound 1 is superior when aqueous hydrogen peroxide is used, allowing near-quantitative conversion of the olefin to the epoxide. With H2O2, compounds 1 and [MoO3(2,2'-bpy)] act as sources of soluble active species, namely, the oxodiperoxo complex [MO(O2)2(2,2'-bpy)], which is formed in situ. Compounds 1 and [WO(O2)2(2,2'-bpy)] (2) were further tested in the epoxidation of cyclododecene, trans-2-octene, 1-octene, (R)-limonene, and styrene. The structure of 2 was determined by single-crystal X-ray diffraction and found to be isotypical with the molybdenum analogue.

Flexible Structure of a Thermally Stable Hybrid Aluminosilicate Built with Only the Three-Ring Unit

Organic–inorganic aluminosilicate hybrids are an attractive new class of materials that add organic functionalities to conventional properties of solid inorganic catalysts. ECS-17, a novel crystalline hybrid, was synthesized using 1,4-bis-(triethoxysilyl)-benzene as the sole silicon source. Its structure was solved by direct methods starting from high-resolution synchrotron X-ray diffraction data and is composed of inorganic layers, characterized by 10 rings, held together by phenylene rings. ECS-17 is the first aluminosilicate built from only the three-ring secondary building unit. This new material shows intriguing reversible collapsibility upon dehydration/rehydration. Mild thermal treatment under vacuum causes its crystalline structure to collapse due to facile elimination of the water molecules around the cations. Successive exposure to ambient atmospheric moisture gives back the hydrated crystalline form. ECS-17 shows remarkably high thermal stability for a hybrid, being stable up to 450 °C under va...

YbPtGe2: A multivalent charge-ordered system with an unusual spin pseudogap

We performed a study of the structural and physical properties of YbPtGe${}_{2}$. This compound is a multivalent charge-ordered system presenting an unusual spin pseudogap below 200 K. The crystal structure of YbPtGe${}_{2}$ is refined from single-crystal and powder high-resolution synchrotron x-ray diffraction data at different temperatures. Analysis of the structural features of YbPtGe${}_{2}$, together with a combined study of Yb ${L}_{\mathrm{III}}$ x-ray absorption spectroscopy, magnetic susceptibility $\ensuremath{\chi}(T)$, thermopower $S(T)$, and ${}^{171}$Yb and ${}^{195}$Pt NMR indicate half of the Yb atoms to be in an intermediate valence state with an electronic configuration close to 4${f}^{13}$ (Yb${}^{3+}$), while for the remaining Yb atoms the 4${f}^{14}$ (Yb${}^{2+}$) configuration with almost no valence fluctuations is most likely. A drastic drop of the magnetic susceptibility and a decrease of the isotropic shift ${}^{195}{K}_{\mathrm{iso}}(T)$ with decreasing temperature in the temperature range of 50--200 K evidence the opening of a spin pseudogap with an activation energy of $\ensuremath{\Delta}/{k}_{\mathrm{B}}$ $\ensuremath{\sim}$ 200 K. Surprisingly, transport properties do not show clear evidence for the opening of a charge gap, thus excluding a standard Kondo-insulator scenario. Possible origins for this unusual electronic (valence) behavior are discussed.

Evidence for diffuse ferroelectric phase transition and cooperative tricritical freezing of random-site dipoles due to off-centered Bi3+ions in the average cubic lattice of (Ba1−xBix)(Ti1−xFex)O3

The mixed solid solution (Ba${}_{1\ensuremath{-}x}$Bi${}_{x}$)(Ti${}_{1\ensuremath{-}x}$Fe${}_{x}$)O${}_{3}$ (BT-$x$BF) system exhibits nonrelaxor-type diffuse ferroelectric phase transition whose diffuseness increases with increasing concentration of BiFeO${}_{3}$ for $x$ \ensuremath{\le} 0.40. Rietveld analysis of the high-resolution synchrotron x-ray diffraction data reveals that the average cubic symmetry of BT-$x$BF for 0.15 \ensuremath{\le} $x$ \ensuremath{\le} 0.40 is broken locally by the off-centering of the Bi${}^{3+}$ ions with respect to the Ba${}^{2+}$ positions at the perovskite cube corners in the $\ensuremath{\langle}001\ensuremath{\rangle}$ direction. We also show that the random-site dipoles generated by the off-centered Bi ions freeze out cooperatively with a critical exponent of 1/4 characteristic of a tricritical transition. It is argued that the diffuse ferroelectric phase transition in the BT-$x$BF system is due to the formation of random field domains. The static random fields are generated by the local charge imbalances, strain field, or both caused by the presence of off-valent substituents, even though the overall composition is charge neutral.

Cationic disorder, microstructure and dielectric response of ferroelectric SBT ceramics

Polycrystalline samples of SrBi2Ta2O9(acronym SBT) have been prepared by means of solid-state reaction either using a classical route or by mechanochemical activation. For each compound, a structural analysis of the ferroelectric orthorhombic phase (space groupA21am) has been performed from the fitting of neutron and/or X-ray powder diffraction data using the Rietveld method. A cationic disorder on Bi3+and Sr2+crystallographic sites has been revealed, the Sr atoms occupying the Bi sites andvice versa. From diffraction peak broadening analyses of high-resolution synchrotron X-ray diffraction data, it has been shown that the two grinding methods (manual or mechanical) induce local strains, the average apparent strain being three times larger for the mechanically ground sample. In order to link microstructure and ferroelectric properties, the dielectric constant has been measured as a function of the temperature. It appears that the position and the shape of the dielectric anomaly strongly depend upon the composition and the route used to elaborate the powders. More exactly, for the mechanically ground powder, the large apparent strain, probably correlated to the strong cation exchange revealed by the structural refinement, leads to a significantly enhanced dielectric response.

NH 4CoAlF 6: A pyrochlore-related phase existing in both ordered and disordered forms

Single crystals of NH 4CoAlF 6 (I) are grown by hydrofluorothermal synthesis under 3 kbar pressure. A single-crystal, X-ray structural determination showed the compound is orthorhombic and adopts a pyrochlore-related RbNiCrF 6-type structure with an ordered arrangement of Co and Al in the octahedral sites. The observed orthorhombic symmetry is a direct consequence of the cation ordering in the octahedral sites of the pyrochlore lattice. However, NH 4CoAlF 6 (II) synthesized by thermal decomposition of hexaamminecobalt hexafluoroaluminate, (NH 3) 6CoAlF 6, adopts a cubic structure and the structural refinement using high-resolution synchrotron X-ray diffraction data showed this phase also has a structure similar to RbNiCrF 6 but with a disordering of Co and Al atoms in the octahedral sites. The cubic NH 4CoAlF 6 phase (II) is metastable and can be converted to the orthorhombic phase (I) by prolonged heating at 350 °C in a sealed platinum tube. Stabilization of an ordered structure for NH 4CoAlF 6 is apparently due to the significant difference in the ionic radii of octahedrally coordinated Co 2+ and A1 3+ cations.

Rietveld study of the structural phase transition in the sanmartinite (ZnWO4)-cuproscheelite (CuWO4) solid solution

The P to Pile phase transition in Cui. ΛZnxWO4 has been investigated by observing structural changes across the solid solution. The crystal structures of samples with x = 0.85, 0.55 and 0.30 have been refined by the Rietveld method from high-resolution synchrotron X-ray diffraction data. The Cu/Zn and W atoms are in distorted octahedral coordination. The microscopic order parameter (defined in terms of changes in Cu/Zn-O bond lengths) behaves in a similar manner to the previously-recorded macroscopic spontaneous strain. Rigid-unit-mode analysis shows that the transition does not involve distortions of a framework of rigid octahedra. Rather, the co-operative Jahn-Teller distortion of the CuO6 octahedra is identified as the driving mechanism, with WO6 octahedral distortions occurring as a secondary process.

Structure of La 5Cu 5O 13.35 by High-Resolution Synchrotron X-Ray Diffraction

The structure of La 5Cu 5O 13.35 was refined from high-resolution synchrotron X-ray diffraction data using the Rietveld method. The unit cell is monoclinic, space group P 2/ m- C 12 h (No. 10), with a = 8.62884(5) Å, b = 3.83076(2) Å, c = 8.65148(5) Å, β = 90.2166(4)°, V = 285.973(4) Å 3, Z = 1, D x = 7.085 g/cm 3 at T = 300 K. 265 independent reflections were included in the refinement and a reasonably good fit was obtained with final R values R I = 9.28%, R p = 14.51%, R wp = 19.60%, and goodness-of-fit S wp = 1.573. The structure is of the oxygen-defect Perovskite type and is composed of one distorted CuO 6 octahedron and four distorted CuO 5 square pyramids per crystallographic unit cell. The polyhedra of La 5Cu 5O 13+δ display a three-dimensional connectivity with a unique oxygen ordering which creates one-dimensional channels of vacancies along the b-axis.