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Hydrogen zirconium phosphate (HZP) is a ceramic material with the formula HZr 2 (PO 4) 3 that can potentially offer anhydrous protonic conductivity, with thermostability for the intrinsic protons up to 650 °C, and good chemical stability in aqueous environments or acid gases. Despite the attraction of these features for electrolyte applications, such as gas separation, fuel cells or electrolysers, work on this material remains in its infancy. A possible reason for this lack of attention may be related to the complexity to obtain the HZP material as a pure phase. For this reason, the current article examines a new hydrothermal synthesis method to produce the ammonium precursor, NH 4 Zr 2 (PO 4) 3 , in its phase pure form, and consequently a refined overall route to produce the desired HZP target material. In the synthesis of the ammonium precursor, we underscore the precise control of reaction conditions that are necessary to obtain the pure NH 4 Zr 2 (PO 4) 3 material, both in its cubic and hexagonal structural polymorphs. For reaction times of 10 h, the cubic phase is obtained by employing a hydrothermal temperature of 150 °C and an aqueous ammonia volume of 2.1 mL, while the hexagonal phase is obtained for a hydrothermal temperature of 200 °C and an aqueous ammonia volume between 2.3 and 2.4 mL. Subsequently, we investigate the required conditions to convert hexagonal NH 4 Zr 2 (PO 4) 3 fully to hexagonal HZr 2 (PO 4) 3 via thermal treatment at 600 °C for 5 h, assessed by a combination of X-ray diffraction and infrared spectroscopy. In this way this article aims to open up further research on this interesting HZP material by documenting a robust route for its preparation. [ABSTRACT FROM AUTHOR]

The structure, microstructure, coefficient of thermal expansion (CTE), and mechanical properties of Na1+2xZr2−xCox(PO4)3 ceramics (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) were studied. Na1+2xZr2−xCox(PO4)3 submicron powders with the NaZr2(PO4)3 structure (NZP, kosnarite type) were obtained by the solid-phase method. The starting reagents (NaNO3, ZrOCl2·8H2O, NH4H2PO4, CoCl2·6H2O, ethanol) were mixed with the addition of ethyl alcohol. The resulting mixtures were annealed at 600 °C (20 h) and 700 °C (20 h). The obtained phosphates crystallized in the expected structure of the NaZr2(PO4)3 type (trigonal system, space group R3¯c). Thermal expansion of the powders was studied with high-temperature X-ray diffraction at temperatures ranging from 25 to 700 °C. CTEs were calculated, and their dependence on the cobalt content was analyzed. Na1+2xZr2−xCox(PO4)3 ceramics with high relative density (93.67–99.70%) were obtained by Spark Plasma Sintering (SPS). Ceramics poor in cobalt (x = 0.1) were found to have a high relative density (98.87%) and a uniform fine-grained microstructure with a grain size of 0.5–1 µm. Bigger cobalt content leads to a smaller relative density of ceramics. During the sintering of ceramics with high cobalt content, anomalous grain growth was observed. The powder compaction rate was shown to be determined by creep and diffusion intensity in the Na1+2xZr2−xCox(PO4)3 crystal lattice. SPS activation energy in ceramics increased as the cobalt content grew. The microhardness and fracture toughness of ceramics did not depend on their cobalt content.

The structure, microstructure, coefficient of thermal expansion (CTE), and mechanical properties of Na1+2xZr2−xCox(PO4)3 ceramics (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) were studied. Na1+2xZr2−xCox(PO4)3 submicron powders with the NaZr2(PO4)3 structure (NZP, kosnarite type) were obtained by the solid-phase method. The starting reagents (NaNO3, ZrOCl2·8H2O, NH4H2PO4, CoCl2·6H2O, ethanol) were mixed with the addition of ethyl alcohol. The resulting mixtures were annealed at 600 °C (20 h) and 700 °C (20 h). The obtained phosphates crystallized in the expected structure of the NaZr2(PO4)3 type (trigonal system, space group R 3 ¯ c). Thermal expansion of the powders was studied with high-temperature X-ray diffraction at temperatures ranging from 25 to 700 °C. CTEs were calculated, and their dependence on the cobalt content was analyzed. Na1+2xZr2−xCox(PO4)3 ceramics with high relative density (93.67–99.70%) were obtained by Spark Plasma Sintering (SPS). Ceramics poor in cobalt (x = 0.1) were found to have a high relative density (98.87%) and a uniform fine-grained microstructure with a grain size of 0.5–1 µm. Bigger cobalt content leads to a smaller relative density of ceramics. During the sintering of ceramics with high cobalt content, anomalous grain growth was observed. The powder compaction rate was shown to be determined by creep and diffusion intensity in the Na1+2xZr2−xCox(PO4)3 crystal lattice. SPS activation energy in ceramics increased as the cobalt content grew. The microhardness and fracture toughness of ceramics did not depend on their cobalt content. [ABSTRACT FROM AUTHOR]

Phosphates Na1 –xR0.33xTi2(PO4)3 (R = Y or La; 0 ≤ х ≤ 1) were synthesized by the Pechini process and characterized by X-ray diffraction, electron microscopy with microprobe analysis, and IR spectroscopy. The systems exhibit isodimorphism to form a series of solid solutions belonging to the NaZr2(PO4)3 (NZP) structural type and crystallizing in space group R c or R The Rietveld structural studies confirmed the isomorphic miscibility of sodium and the rare-earth element in the interstices of the NZP structure. The unit cell parameter с in the phosphates studied tends to increase, and the parameter а tends to decrease, in response to rising temperature, which trends are typical of NZP phosphates. [ABSTRACT FROM AUTHOR]

Submicron-grade powders of Na1-xZr2(PO4)3-x(XO4)x compounds (hereafter referred to as NZP) and Ca1-xZr2(PO4)3-x(XO4)x compounds (hereafter, CZP), X = Mo, W (0 ≤ x ≤ 0.5) were obtained by sol-gel synthesis. The compounds obtained were studied by X-ray diffraction phase analysis and electron microscopy. An increase in the W or Mo contents was shown to result in an increase in the unit cell volume of the NZP and CZP crystal lattices and in a decrease in the coherent scattering region sizes. Thermal expansion behavior at high temperatures of synthesized NZP and CZP compounds has been investigated. The dependencies of the parameters a and c on the heating temperature, as well as the temperature dependence of the crystal lattice unit cell volume V in the range from the room temperature up to 800 °C, were obtained. The dependencies of the average thermal expansion coefficient (αav) and of the volume coefficient (β) on the W and Mo contents in the compositions of NZP and CZP compounds were studied. Ceramics Na1-xZr2(PO4)3-x(XO4)x with relatively high density (more than 97.5%) were produced by spark plasma sintering (SPS). The increase in the W or Mo contents in the ceramics leads to an increase in the relative density of NZP and to a decrease of the optimum sintering temperature. The mean grain size in the NZP ceramics decreases with increasing W or Mo contents. The study of strength characteristics has revealed that the hardness of the NZP ceramics is greater than 5 GPa, and that the minimum fracture toughness factor was 1 MPa·m1/2. [ABSTRACT FROM AUTHOR]

This paper introduces the results of hydrolytic stability tests and radiation resistance tests of phosphate molybdates and phosphate tungstates Na1−xZr2(PO4)3−x(XO4)x, X = Mo, W (0 ≤ x ≤ 0.5). The ceramics characterized by relatively high density (more than 97.5%) were produced by spark plasma sintering (SPS) of submicron powders obtained by sol–gel synthesis. The study focused on hydrolytic resistance of the ceramics in static mode at room temperature. After 28 days of testing in distilled water, the normalized leaching rate was determined. It was found that the ceramics demonstrated high hydrolytic resistance in static mode: the normalized leaching rates for Mo- and W-containing ceramics were 31·10−6 and 3.36·10−6 g·cm−2·day−1, respectively. The ceramics demonstrated high resistance to irradiation with 167 MeV Xe+26 multiple-charged ions at fluences ranging from 1·1012 to 6·1013 cm−2. The Mo-containing Na0.5Zr2(PO4)2.5(XO4)0.5 ceramics were shown to have higher radiation resistance than phosphate tungstates. Radiation was shown to trigger an increase in leaching rates for W and Mo in the crystal structure of NZP ceramics. [ABSTRACT FROM AUTHOR]

Sodium zirconium phosphate (NaZr 2 (PO 4) 3 , NZP) type phosphate compounds have been considered as a candidate material for the immobilization of radionuclides. In this work, the highly densified NZP-type ceramic waste forms for immobilizing simulated radionuclides Sr and Cs, which were designed as the formula of Cs 1-2 x Sr x Zr 2 (PO 4) 3 (x = 0, 1/12, 2/12, 3/12, 4/12, 5/12, and 6/12), were prepared by microwave-assisted solid-state sintering method. The effects of Sr and Cs incorporation on the phase composition, microstructure, densification, and chemical durability of Cs 1-2x Sr x Zr 2 (PO 4) 3 ceramic waste forms were systematically discussed. It was shown that the single CsZr 2 (PO 4) 3 (CsZP) phase was generated in the samples when x ≤ 2/12, while two phases of CsZP and Sr 0.5 Zr 2 (PO 4) 3 (SrZP) were formed when 3/12 ≤ x ≤ 5/12. The Rietveld refinement results revealed that Sr/Cs could be incorporated in the NZP crystal structure. The as-prepared samples all presented a well dense microstructure, whose relative density reached up to approximately 98% with Sr incorporation. In addition, the Product Consistency Test (PCT) leaching results demonstrated that the ceramics waste forms simultaneously immobilizing Sr and Cs exhibited superior leaching resistance, and the leaching rates of Sr and Cs elements were in the order of 10−3-10−4 g m−2 d−1. The increase of Sr incorporation brought about the decreased leaching rates of ceramic samples. [ABSTRACT FROM AUTHOR]

This paper introduces the results of hydrolytic stability tests and radiation resistance tests of phosphate molybdates and phosphate tungstates Na1−xZr2(PO4)3−x(XO4)x, X = Mo, W (0 ≤ x ≤ 0.5). The ceramics characterized by relatively high density (more than 97.5%) were produced by spark plasma sintering (SPS) of submicron powders obtained by sol–gel synthesis. The study focused on hydrolytic resistance of the ceramics in static mode at room temperature. After 28 days of testing in distilled water, the normalized leaching rate was determined. It was found that the ceramics demonstrated high hydrolytic resistance in static mode: the normalized leaching rates for Mo- and W-containing ceramics were 31·10−6 and 3.36·10−6 g·cm−2·day−1, respectively. The ceramics demonstrated high resistance to irradiation with 167 MeV Xe+26 multiple-charged ions at fluences ranging from 1·1012 to 6·1013 cm−2. The Mo-containing Na0.5Zr2(PO4)2.5(XO4)0.5 ceramics were shown to have higher radiation resistance than phosphate tungstates. Radiation was shown to trigger an increase in leaching rates for W and Mo in the crystal structure of NZP ceramics.

Submicron-grade powders of Na1-xZr2(PO4)3-x(XO4)x compounds (hereafter referred to as NZP) and Ca1-xZr2(PO4)3-x(XO4)x compounds (hereafter, CZP), X = Mo, W (0 ≤ x ≤ 0.5) were obtained by sol-gel synthesis. The compounds obtained were studied by X-ray diffraction phase analysis and electron microscopy. An increase in the W or Mo contents was shown to result in an increase in the unit cell volume of the NZP and CZP crystal lattices and in a decrease in the coherent scattering region sizes. Thermal expansion behavior at high temperatures of synthesized NZP and CZP compounds has been investigated. The dependencies of the parameters a and c on the heating temperature, as well as the temperature dependence of the crystal lattice unit cell volume V in the range from the room temperature up to 800 °C, were obtained. The dependencies of the average thermal expansion coefficient (αav) and of the volume coefficient (β) on the W and Mo contents in the compositions of NZP and CZP compounds were studied. Ceramics Na1-xZr2(PO4)3-x(XO4)x with relatively high density (more than 97.5%) were produced by spark plasma sintering (SPS). The increase in the W or Mo contents in the ceramics leads to an increase in the relative density of NZP and to a decrease of the optimum sintering temperature. The mean grain size in the NZP ceramics decreases with increasing W or Mo contents. The study of strength characteristics has revealed that the hardness of the NZP ceramics is greater than 5 GPa, and that the minimum fracture toughness factor was 1 MPa·m1/2.

New NZP-type solid solutions, Na1+2xZr2–xNix(PO4)3 and Ca0.5+xZr2–xNix(PO4)3 with x = 0.10, 0.25, and 0.50, have been prepared by solid-state reactions. The synthesized samples have been characterized by X-ray diffraction and IR spectroscopy. Crystal structure of the compound CaZr1.5Ni0.5(PO4)3 has been refined by full-profile X-ray diffraction analysis method, reliability factors is Rp = 4.78% and Rwp = 6.45%, respectively. Thermal expansion of the phosphates has been studied by high-temperature X-ray diffraction in the temperature range 25–700°C. The synthesized compounds have been shown to be intermediate- and low-thermal-expansion materials. Using SPS method we have produced ceramic samples with a high relative density (ρrel > 97%), based on phosphate powders. Strength characteristics (microhardness and fracture toughness) of the ceramics have been determined. [ABSTRACT FROM AUTHOR]

The crystal-chemical approach has been applied to design materials with regulated thermal expansion. To that end, model simulations have been performed for compositions of phosphates that yield solid solutions of the following type Na1 + 2xZr2 –xCux(PO4)3 and Ca0.5 +xZr2 –xCux(PO4)3, 0.1 ≤ x ≤ 0.5 with the expected structure of NaZr2(PO4)3 (NZP). The new phosphates have been prepared by solid-state reactions and characterized by X‑ray diffraction, IR spectroscopy, and scanning electron microscopy. The compounds have been shown to crystallize in the NZP structure, with a particle size from 0.1 to 1 μm. The thermal expansion of the compounds has been studied by high-temperature X-ray diffraction in the temperature range from 25 to 700°C. Linear, average, and volume coefficients of thermal expansion and anisotropy of thermal expansion have been calculated and analyzed in relation to composition of Na, Zr, Cu and Ca, Zr, Cu phosphates in the studied sets. [ABSTRACT FROM AUTHOR]

The new phosphates ZnxMg0.5+xE2−x(PO4)3 (E = Ti, Zr) were synthesized by the sol–gel method followed by heat treatment. Obtained samples were characterized with X-ray, IR, DTA and microprobe electron analyses. The ZnxMg0.5+xTi2−x(PO4)3 solid solution (0 ≤ x ≤ 0.5, kosnarite-type, sp. gr. R 3 ¯ ) is stable up to 1323 K. The ZnxMg0.5+xZr2−x(PO4)3 solid solution (0 ≤ x ≤ 0.5, Sc2(WO4)3-type, sp. gr. P21/n) is thermally unstable above 1273 K. The thermal expansion of ZnxMg0.5+xE2−x(PO4)3 solid solutions was studied in the temperature range 298–1073 K. The magnitudes of average volume thermal expansion coefficients vary from 1 × 10−5 to 5 × 10−6 K−1. The composition regulation of these medium- and high-expanding materials allows you to change the characteristics of thermal expansion in the required direction. [ABSTRACT FROM AUTHOR]

Abstract—: Ca0.75 + 0.5xZr1.5Fe0.5(PO4)3 -x(SiO4)x (x = 0-0.5) solid solutions have been synthesized by a sol-gel process and characterized by X-ray diffraction, IR spectroscopy, and differential scanning calorimetry. As expected, the synthesized phosphatosilicates crystallize in a NaZr2(PO4)3-type structure (trigonal symmetry, sp. gr. Rc). The thermal expansion of the solid solutions has been studied by high-temperature X-ray diffraction in the temperature range from 25 to 800°C. Their thermal expansion parameters have been calculated and analyzed as functions of composition. High-density ceramics based on the Ca0.875Zr1.5Fe0.5(PO4)2.75(SiO4)0.25 phosphatosilicate have been produced by spark plasma sintering and their structure and properties have been studied in detail. [ABSTRACT FROM AUTHOR]

Ca0.5(1 + x)Zr2-xFex(PO4)3 phosphates have been synthesized by a sol-gel process. The individual compounds and solid solutions obtained crystallize in the NaZr2(PO4)3 structure (trigonal symmetry, sp. gr. R3¯). Using high-temperature X-ray diffraction, we have determined their thermal expansion parameters in the temperature range from 25 to 800°C. With increasing x, the magnitudes of their linear thermal expansion coefficients and thermal expansion anisotropy decrease. Most of the synthesized phosphates can be rated as low-thermal-expansion compounds and can be regarded as materials capable of withstanding thermal “stress.” [ABSTRACT FROM AUTHOR]

The review covers aspects of modeling the composition and luminescent properties of phosphates of NaZr2(PO4)3 (NZP) and langbeinite structural families. Based on the analysis of phosphates structure, a plausible algorithm of the use of crystal chemistry data for modeling compositions, structure, and properties of new compounds is proposed. The following properties determined by requirements to materials for the chosen purposes are studied: behavior on heating and in water systems, luminescence, and biocompatibility. Prospects for the use of such data for solving various problems of materials science, LED technologies, bioimaging, and X-ray induced photodynamic therapy of oncological diseases are shown. [ABSTRACT FROM AUTHOR]

The solid solution row AEu $^{\mathrm {3+}}_ {x}$ Zr(PO), where A = Na, K, Rb, Cs and x ranging from 0 to 0.25 was obtained by methods based on sol-gel processes in the presence of the salting-out agent, CHOH. The formation of phases of the structural type NaZr(PO) (NZP) and their crystallization in the crystal forms belonging to the space group ${\boldsymbol {R\bar {{3}}c}}$ (0 ≤x≤ 0.1) and $\boldsymbol {{P\bar {{3}}c}}$ ( x= 0.25) were determined. Morphotropic transition occurred. Trivalent europium was included as a local probe. Its electric and magnetic dipole was used to characterize the substitution rule and the localization of this cation in the structure, which is in agreement with the structural characterization. It appears that europium is located in the M1 and M2 sites as a function of the Eu concentration. [ABSTRACT FROM AUTHOR]

[Display omitted] • OZP had a higher ethanol production, and NZP had a higher acidity within it. • The ZP fermentation process in SFB can be clearly divided into phase I (0-15d) and phase II (25-40d). • Monascus and Trichosporon are the unique dominant functional fungi observed in the phase II of OZP. • 2 bacterial (Lactobacillus and Acetobacter) and 6 fungal (Monascus, Issatchenkia, Trichosporon, unclassified_f_Sordariaceae, Xeromyces, and Kazachstania) genera were identified as core functional microorganisms linked to the variations in volatile metabolites during the fermentation process. Differences between the old and young pit mud in a pit cellar enlarged differences in Zaopei (ZP) fermentation to varying degrees, ultimately affecting the aromatic quality of the Baijiu that is produced. The whole fermentation process could be divided into two phases, namely phase I (0_15 days) and phase II (25_40 days) based on the dynamics of the diversity of microbial communities. Starch and reducing sugar in phase I were used more rapidly by microflora, leading to a higher ethanol production in ZP within an old pit mud (OZP) and a higher acidity in ZP within a new pit mud (NZP), and resulting in different microbial succession patterns therein. Lactobacillus became the dominant bacteria more rapidly in OZP but maintained its abundance in NZP. Monascus and Trichosporon were the unique dominant functional fungi observed in the phase II of OZP. Two bacterial and six fungal genera were identified as core functional microorganisms linked to the variations in volatile metabolites during the fermentation process, ultimately resulting in a higher ester content in OZP and improved liquor quality. This study demonstrated the effect of new and old pit muds on ZP fermentation, and its findings can guide the future artificial regulation of NZP. [ABSTRACT FROM AUTHOR]

Fluoride anion interaction has been explored for the first time to investigate how the structure of sodium zirconium phosphate (NZP) and calcium zirconium phosphate (CZP) can be altered in its presence. Different compositions were made by adding NaF and CaF in CZP and NZP matrices respectively. Fluoride interaction differs with NZP and CZP structure as suggested by F-NMR data. The addition of fluoride to the NZP or CZP structure enables to stabilize the structure at a low temperature of 600-700 °C under microwave conditions. [ABSTRACT FROM AUTHOR]

Preliminary data were obtained on the immobilization of various heterovalent ions present in the two selected high-level nuclear waste compositions. The entire set of ions present in the waste compositions were immobilized into sodium zirconium phosphate (NZP) structure. The waste loading was in the range 5-25%. The two types of wasteforms loaded with the simulated high-level waste compositions were characterized by powder X-ray diffraction, FT-IR, TGA/DTA, and scanning electron microscopy. The difference in the compositions of the two simulated wastes was reflected in the waste loading percentage and the crystallization of the wasteforms into NZP structure. Up to 12% waste loading, single phase isostructural with NZP was obtained as a major product in the case of the first waste composition. An increase in the waste loading led to the segregation of ZrPO as a secondary phase. With the second waste composition, an NZP-like phase was obtained as the major product even at 25% waste loading. [ABSTRACT FROM AUTHOR]

Quench protection is one of the most important issues for magnet applications using 2 G HTS tapes because of their non-self-protecting properties. Although many researchers have examined the quench/recovery characteristics of HTS magnets to establish the required stability, new information on the quench/recovery characteristics of the recently commercialized HTS magnet with GdBCO CC is needed. In this study, the quench/recovery characteristics of Zr-doped (Gd,Y)BCO CC pancake coils that were insulated with various materials, such as copper and Kapton tapes, were examined in a liquid nitrogen (LN2) bath. The minimum quench energy (MQE) and normal zone propagation (NZP) velocity of the Zr-doped (Gd,Y)BCO CC pancake coils are discussed in terms of the quench/recovery test results. [ABSTRACT FROM AUTHOR]

YBCO coated conductor (CC) is useful for application to the insert coil for the NMR because of its great property on critical current under high magnetic field. For the safe operation of CC magnets, design of the stabilizer is imperative issue. The minimum quench energy, minimum propagation zone (MPZ), and quench propagation velocity are obviously affected by both properties and thickness of the stabilizer. In this paper, stacks of CCs were used to be partly substituted for a double pancake magnet for simplicity in experiments, and the CCs in a stack were pressed from top and bottom to enhance thermal and electrical contact. The heater made of Hastelloy C-276 was attached to initiate quench. The stacks which comprise only CCs and pairs of CC and additional copper tape were fabricated, and tests of longitudinal and transverse quench propagation in the stack were carried out in both liquid nitrogen (LN2) of 77 K and liquid helium (LHe) of 4.2 K. Copper tapes were attached on each CC without soldering in the stack for the tests to see effects of the thickness of stabilizer and the contact between CC and copper tape. Numerical analysis was performed by using finite element method (FEM). Comparisons of experiment and simulation results were reported and discussed from the point of view of magnet stability and protection. [ABSTRACT FROM AUTHOR]

Abstract: The high-temperature enthalpy increments of the phosphates La1/3Zr2(PO4)3, Nd1/3Zr2(PO4)3, Eu1/3Zr2(PO4)3 and Lu1/3Zr2(PO4)3 have been measured by high-temperature drop calorimetry in the temperature range 484.5–1090.7K. From these results the heat capacity of the studied compounds has been derived. [Copyright &y& Elsevier]

Abstract: Chromium-containing NASICON-related phosphates of the type Na(1+x)Cr x M(2−x)P3O12) (M=Ti, Hf, Zr) have been synthesised by solid state reaction and structurally characterised by Rietveld refinement of the powder X-ray diffraction data. Materials of composition A(1+x)/2Cr x Zr(2−x)P3O12 (A=Cd, Ca, Sr), have also been prepared and characterised. The crystal structure of Na(1+x)Cr x M(2−x)P3O12 corresponds to R-3c symmetry for x values ranging from 0.15 to 2.00, whereas compounds of composition A(1+x)/2Cr x Zr(2−x)P3O12 corresponding to R-3c are obtained when x ≤1.00 for Sr2+ and Ca2+, and x ≤1.50 for Cd2+. The polarizing effect of the two different metal ions A and M on the phosphorus atom and the P–O bond was studied by both 31P MAS NMR and infrared spectroscopy and shows that the electron density on the phosphorus, and thus the strength of the P–O bonds, are affected by both the interstitial (A) and the structural (M) metal ions. [Copyright &y& Elsevier]

Abstract: Crystal structures of synthetic phosphates Ce0.33Zr2(PO4)3, Eu0.33Zr2(PO4)3 and Yb0.33Zr2(PO4)3 have been refined by Rietveld method using powder diffraction data. Unit cell parameters: a=8.7419 (4), c=23.128 (2)Å; a=8.7659 (1), c=22.822 (1) Å; a=8.8078 (4), c=22.485 (3)Å, respectively; Z=6. Values of final R-factors in isotropic approximation: R wp=4.00, R wp=3.33, R wp=4.12%, respectively. New space group P3¯c has been established for the compounds with general formula Ln 0.33Zr2(PO4)3, where Ln=Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y. It has been confirmed that the synthetic phosphates with general formula Ln 0.33Zr2(PO4)3 belong to the NZP (sodium zirconium phosphate) structure type. [Copyright &y& Elsevier]

Li atoms can be inserted electrochemically into the vacant sites in the host framework structure of hexagonal Cr0.5Nb1.5(PO4)3 (an analog of Nasicon). Intercalation of lithium into this compound is achieved electrochemically at room temperature. The compound, Cr0.5Nb1.5(PO4)3, is used as a cathode of a secondary battery without any lithium initially present in the starting material. The performance of this material is discussed in view of its discharge. XRD, SEM and ESCA spectral studies are carried out on electrode surfaces before and after the insertion/extraction reactions and the results are presented. [Copyright &y& Elsevier]