12194-71-7

Basic information

• Product Name: perovskite
• Synonyms: perovskite;Calcium titanate(IV);Metatitanic acid calcium salt
• CAS NO: 12194-71-7
• Molecular Formula: Ca. O3 Ti
• Molecular Weight: 0
• Mol File: 12194-71-7.mol
• Article Data: 161

Chemical Properties

• Appearance: /
• CAS DataBase Reference: perovskite(CAS DataBase Reference)
• NIST Chemistry Reference: perovskite(12194-71-7)
• EPA Substance Registry System: perovskite(12194-71-7)

Safety Data

• Hazardous Substances Data: 12194-71-7(Hazardous Substances Data)

Usage

InChI:InChI=1/Ca.3O.Ti/q+2;;;;-2/rCa.O3Ti/c;1-4(2)3/q+2;-2

Upstream product

• 546-68-9 titanium(IV) isopropylate 
• 112926-00-8 silica gel 
• 16043-45-1 titanium(IV) 
• 14127-61-8 calcium(II) ion 
• 14336-71-1 calcium chloride 

Downstream Products

• 12045-63-5 titanium diboride 

Relevant articles and documents

Thermal expansion and electrical conductivity of CaTi0.9M 0.1O3-δ (M = Fe, Cu, Al)

The thermal expansion of CaTi0.9M0.1O 3-δ (M = Fe, Cu, Al) samples has been measured, and their lattice parameters have been refined in space group Pnma. The three materials are shown to be mixed conductors, p-type at high

Correlation between the dielectric properties and local electronic structure of copper doped calcium titanate

Copper-doped calcium titanate (CuxCa1-xTiO 3, x = 0.0, 0.01, 0.02 and 0.03) ceramic system was synthesized using solid state reaction method. X-ray diffraction and Raman spectroscopic studies reveal the presence of Pbnm sp

MIITiO(C2O4)2 · 4H2O (MII = Mg, Ca, Sr or Ba) as precursors in the formation of MIITiO3 powders

A synthesis route is described for the preparation of the alkaline earth metal titanyl oxalates MIITiO(C2O4)2·4H2O (MII=Mg, Ca, Sr or Ba). The thermal decompositions of these compounds were studied by means of DTA and TG in comparisons with X-ray measurements. The final products MIITiO3 were characterized morphologically.

Dielectric and ordering behavior in PbxCa1-xTiO3

The dielectric properties and microstructure of PbxCa1-xTiO3 are reported. At room temperature, PbxCa1-xTiO3 is orthorhombic for compositions where x is 0.1 and 0.2, pseudocubic for composi

A novel method of synthesis and microstructural investigation of calcium titanate powders

A novel method, using calcium chloride bihydrate (CaCl2·2H2O and TiO2) as raw materials, to synthesize crystalline calcium titanate (CaTiO3) has been investigated by thermodynamic calculation and X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), differential scanning calorimetric-thermogravimetric analysis (DSC-TG), high resolution transmission electron microscopy (HR-TEM) etc. Using XRD technique analyzed experimental results revealed success of thermal sintering process, in which the mass ratio of M CaCl2·2H2O/MTiO2?=?2:1, holding temperature of 1073?K, preservation time 2?h, could be used to produce crystalline CaTiO3powders. Ratio of Ca/Ti/O?=?1:1:3 was verified by EDS pot-scan. According to SEM observation, the crystalline CaTiO3powders are mainly composed of many separated particles with average size approximately 10?μm and have been demonstrated a strongly faceted morphology. The lattice plane, (112) is clearly observed in the HR-TEM micrograph and the lattice distance was measured as 0.27?nm.

Preparation and electrical properties of xCaRuO3/(1 - x)CaTiO3 perovskite composites

CaRuO3-CaTiO3 ceramic composites were prepared by sintering for short times for potential applications in the areas of electronic ceramics. Scanning electron microscopy and energy dispersive X-ray analysis showed two separate phases,

Characterization of MgTiO3-CaTiO3-layered microwave dielectric resonators with TE01δ mode

MgTiO3 and CaTiO3 ceramics were stacked in different schemes as the key components of the microwave dielectric resonators, and the microwave dielectric characteristics were evaluated with TE01δ resonant mode. With increasi

Role of lithium borosilicate glass in the decomposition of MgTiO3-based dielectric ceramic during sintering

The decomposition behaviour of 0.9MgTiO3-0.1CaTiO3 dielectric ceramic during a liquid phase sintering by lithium borosilicate (LBS) glass was studied. The decompositions of MgTiO3 into MgTi2O5 and Mg

Long-lived photoinduced charge-carriers in Er3 + doped CaTiO3 for photocatalytic H2 production under UV irradiation

The incorporation of Er3+ ions in the CaTiO3 structure provides an enhanced H2 photoproduction due to the formation of long-lived charge-carriers in the semiconductor. Nitroblue tetrazolium reaction, photoluminescence and time resolved microwave conductivity techniques were used to investigate the generation of the superoxide species and the lifetime of the charge-carriers. The improved photoactivity has been explained in terms of the dopant agent, finding that phenomena such as a higher concentration of the superoxide radicals, a more efficient separation of the photogenerated charge-carriers, and a slower recombination process take place in the Er3 + doped CaTiO3 compared to the undoped CaTiO3.

High-temperature hydroxyapatite-titanium interaction

Hydroxyapatite-titanium interaction has been studied in the temperature range 700 to 1200°C with a view to designing biocompatible dispersion-hardened hydroxyapatite-matrix materials for bone implants. The sequence of phase transformations in hydroxyapatite-titanium powder mixtures during heating in air has been identified using IR spectroscopy, differential thermal analysis, and X-ray diffraction. It is shown that hydroxyapatite decomposition can be inhibited via heat treatment in an atmosphere containing carbon monoxide.

Evolution of crystallographic phases in (Sr1-xCax)TiO3 with composition (x)

Results of X-ray powder diffraction, neutron powder diffraction, electron microdiffraction, and convergent beam electron diffraction (CBED) studies are presented to show that the space group of (S1-xCax)TiO3 (SCT) in the c

Microstructural and electrical properties of CaTiO3-CaCu3Ti4O12 ceramics

This study investigates the microstructure and dielectric properties of (CTO)1-x-(CCTO)x ceramics. X-ray diffraction (XRD) patterns show that the crystal phases of polycrystalline CCTO exhibit a (2 2 0) preferential orientation at the molar fraction x = 1. For (CTO)2/3-(CCTO)1/3 or (CTO)1/3-(CCTO)2/3 ceramics, the crystalline structures of CTO and CCTO coexist at x = 1/3 and 2/3, respectively. Surface scanning electron microscope (SEM) morphologies show that the CCTO with x = 1 sintered above 1010 °C exhibits liquid-phase secondary recrystallization (LPSR) regions, and these regions expand as the sintering temperature increases. Therefore, the grain size and ceramics density depends on the sintering temperature and composition. This suggests that CCTO prepared at x = 1 can be a good candidate for capacitor applications because of its high ε value. The dielectric properties of CCTO sintered at 1100 °C include a dielectric constant (ε) of 23,600, dielectric loss (tan δ) of 0.406 at 10 kHz, leakage current density (J) of 6.11 × 10-6 A/cm2 and conductivity (σ) of 6.11 × 10-9 Ω cm-1 at 1 kV/cm.

Variable temperature in situ X-ray diffraction study of mechanically activated synthesis of calcium titanate, CaTiO3

The effect of mechanical activation on formation of calcium titanate (CaTiO3) from calcined mixtures of CaCO3 and TiO2 was studied by monitoring the course of this solid-state reaction by variable temperature in situ X-ray diffraction (XRD) experiments, scanning electron microscopy (SEM) and dilatometry. Two equimolar mixtures of powdered CaCO3 and TiO2 were prepared: one was mechanically activated by grinding in a high energy vibro-mill. A total of 32 X-ray diffraction data sets for each sample, collected between 30 and 1100°C, were analyzed by multiphase Rietveld refinement. Quantitative phase analysis and microstructure analysis obtained from X-ray diffraction are correlated to results of scanning electron microscopy and dilatometry. In the non-activated sample, small quantities of the reactants remain in the product until 1100°C. In the activated sample, the reaction results in pure CaTiO3 at 920°C.

Short-range structure and photoluminescent properties of the CaTiO3:Pr,La phosphor

Pr3+-doped CaTiO3perovskite is a promising phosphor compound with the possibility of use in several technological applications. In this paper, we report the substitution of Ca2+ions with La3+ions in order to pro

Investigations of the electronic structure of d0 transition metal oxides belonging to the perovskite family

Computational and experimental studies using linear muffin tin orbital methods and UV-visible diffuse reflectance spectroscopy, respectively, were performed to quantitatively probe the relationships between composition, crystal structure and the electronic structure of oxides containing octahedrally coordinated d0 transition metal ions. The ions investigated in this study (Ti4+, Nb5+, Ta5+, Mo6+, and W6+) were examined primarily in perovskite and perovskite-related structures. In these compounds the top of the valence band is primarily oxygen 2p non-bonding in character, while the conduction band arises from the π* interaction between the transition metal t 2g orbitals and oxygen. For isostructural compounds the band gap increases as the effective electronegativity of the transition metal ion decreases. The effective electronegativity decreases in the following order: Mo6+>W6+>Nb5+～Ti4+> Ta5+. The band gap is also sensitive to changes in the conduction band width, which is maximized for structures possessing linear M-O-M bonds, such as the cubic perovskite structure. As this bond angle decreases (e.g., via octahedral tilting distortions) the conduction band narrows and the band gap increases. Decreasing the dimensionality from 3-D (e.g., the cubic perovskite structure) to 2-D (e.g., the K2NiF4 structure) does not significantly alter the band gap, whereas completely isolating the MO 6 octahedra (e.g., the ordered double perovskite structure) narrows the conduction band width dramatically and leads to a significant increase in the band gap. Inductive effects due to the presence of electropositive spectator cations (alkali, alkaline earth, and rare-earth cations) tend to be small and can generally be neglected.

Study of intrinsic point defects in oxides of the perovskite family: II. Experiment

The electrical conductivity of ATiO3 and A1+B5+O3 perovskite-type oxides converted by vacuum annealing into states with weak and strong compensation between donors and acceptors has been measured. It was shown t

Detection of morphotropic phase boundary in A-site/Ca-substituted Na0.5Bi0.5TiO3 complex oxides ferroelectric system

Vibrational and structural properties of lead-free piezoelectric (1-x)Na0.5Bi0.5TiO3–xCaTiO3 (0 ≤ x ≤ 1.00) solid solutions have been investigated using Raman spectroscopy and X-ray diffraction. Different anomalies were detected and analyzed taking into consideration the phase transition from rhombohedral to orthorhombic phase at room temperature. All Raman bands were interpreted through the variation in the peak positions (frequency) and the corresponding half-widths at half maximum (HWHM) as a function of x. XRD used as a complementary technique to Raman spectroscopy, showed that the rhombohedral – orthorhombic phase transition went gradually through an intermediate phase consisting of a mixture of rhombohedral (R3c) and orthorhombic (Pnma) structures and that the fraction of orthorhombic phase increased with CT composition. The results show that the morphotropic phase boundary (MPB) is located between 0.09 and 0.15.

Yttrium substitution in MTiO3 (M=Ca, Sr, Ba and Ca+Sr+Ba) perovskites and implication for incorporation of fission products into ceramic waste forms

CaTiO3 has been proposed as a ceramic waste form for immobilization of radioactive waste that might include short-lived fission products 137Cs and 90Sr and consequently their decay products 137Ba (stable), 90Y (intermediate), and 90Zr (stable). In order to characterize substitution relations of Y3+ for M2+ (M=Ca, Sr, Ba singly or in combination) in MTiO3, precursor mixtures with nominal atomic ratios of M:Y:Ti=0.75:0.25:1 were synthesized by solid-state reactions. To ensure homogeneous starting material and to explore low temperature behavior of the Ca-Y-Ti-O system, coprecipitated xerogel powder was synthesized and heated to various temperatures for different periods of time. All M-Y-Ti-O systems formed two major phase mixtures of perovskite MTiO3 and pyrochlore Y 2Ti2O7 with low substitution of M2+ by Y3+ in MTiO3 and Y3+ by M2+ in Y2Ti2O7. The study of xerogel confirmed the tendency of the formation of mixtures of CaTiO3 and Y 2Ti2O7 phases, even at lower temperature. The temperature dependence of the substitution of Ca2+ by Y3+ in CaTiO3 appears to be small. Despite the minor substitution of M by Y in the perovskite no significant 90Y3+ build-up is expected to occur in the waste form due to the rapid decay of 90Y3+ relative to that of 90Sr2+.

Enhanced photoluminescence and ultrahigh temperature sensitivity from NaF flux assisted CaTiO3: Pr3+ red emitting phosphor

The Pr3+ doped CaTiO3 red emitting phosphor with enhanced PL and ultrahigh temperature sensing was prepared via NaF flux assisted solid-state reaction. All samples had the orthorhombic perovskite phase and no impurity was found. The typical sample mainly had sphere-like morphology with particle size of ～670 nm. The optical bandgap values were ～3.62–3.63eV. The Pr3+ quenching content was 0.6 mol% and the ET mechanism for quenching was the d-d interaction with the critical distance of 26.09 ?. A certain amount of NaF flux could enhance red emission attributed to 1D2→3H4 transition owing to improving the crystallinity of phosphors and reducing point defects near Pr3+ through the substitution of O2? by F? and Ca2+ by Na+. The energy storage trap (oxygen vacancy) near IVCT state played the key role for trapping electrons, accounting for the LAG emission and the average depth of trap was 0.39 eV. The CIE chromaticity coordinates were very close to that of the ideal red light and the CP was as high as 99.98%. The maximal Sa and Sr was as high as ～0.015 K-1 and～ 5.2% K?1, respectively. The thermal induced relaxation between the 3Pj levels and 1D2 level through the IVCT state was supposed to account for the excellent optical temperature sensing. Our work may provide a useful inspiration for developing ultrahigh sensitive optical temperature sensors.

ENERGETICS OF COMPOUNDS (A2 + B4 + O 3) WITH THE PEROVSKITE STRUCTURE.

The heats of formation from oxides for perovskite compounds, ABO//3(A equals Ca,Sr,Ba,Pb,Cd,B equals Ti,Zr), were determined by high-temperature solution calorimetry using an alkali borate solvent. The values obtained agree with the results of earlier HF solution calorimetry, when available. The heat of formation from the oxides generally becomes more negative the closer the tolerance factor for that perovskite is to unity. The heat of formation can be divided into two contributions, that from changes in electrostatic (Madelung) energy, which becomes more negative as the tolerance factor decreases mainly repulsive interactions.

Low-temperature preparation and properties of ceramics with composition (1-x)CaTiO3-xPbF2-xLiF

Fluorinated ceramics with initial composition (1-x)CaTiO3+xPbF2+xLiF were sintered at 950 °C. The X-ray diffraction (XRD) patterns of the samples showed the formation of a novel solid solution in the initial composition range 0≤x≤0.125. SEM observations were performed on fractured ceramics and DSC analyses were carried out from room temperature up to 600 °C. Three second-order phase transitions were detected for all the samples. Capacitors were prepared from the pre-sintered ceramics then dielectric measurements were performed as a function of temperature in the frequency range 102-4×107 Hz. The ε′r-T curves exhibit the profile of dielectrics for class I capacitors, however the values of tan δ are too high (tan δ≥1%).

A-site deficient perovskite-type compounds in the ternary CaTiO3-LaCrO3-La2/3TiO3 system

Phase equilibriums in the CaTiO3-LaCrO3-La2/3TiO3 quasi-ternary system have been studied by means of high-resolution powder diffraction technique using X-ray and synchrotron radiation. Over 50 La(2+y-2x)/3CaxCryTi1-yO 3 compounds were synthesized by solid-state reactions in air at 1350 °C using La2O3, CaCO3, Cr2O3 and TiO2. Based on the results of X-ray phase and structural analysis, the isothermal section of the CaTiO3-LaCrO3-La2/3TiO3 phase diagram at room temperature is constructed. The A-cation deficient La(2+y-2x)/3CaxCryTi1-yO 3 solid solution with different perovskite-type structures (space groups Pbnm, Imma, I4/mcm and Cmmm or P2/m) is formed in the CaTiO3-LaCrO3-La2/3TiO3 quasi-ternary system in air conditions. The compounds show high stability at high temperatures at reducing as well as at oxidizing conditions. The substances with y = 0 and y = 0.2 show n-type conductivity at 900 °C at pO2 = 10-15 to 105 Pa and with y = 0.5 show conductivity minima these shift to the oxygen reach region with increasing A-site deficiency. The A-site deficient La(2+y-2x)/3CaxCryTi1-yO 3 samples have higher sintering ability in comparison with the cation stoichiometric La1-xCaxCr1-yTiyO3 compositions and, in contrast to the latter, can be prepared as gas dense ceramics in air at temperatures lower as 1300 °C. Thermal expansion of the A-site deficient La(2+y-2x)/3CaxCryTi1-yO 3 ceramics is comparable with that of yttrium stabilised zirconia (YSZ). No interaction between La(2+y-2x)/3CaxCryTi1-yO 3 and YSZ ceramics up to 1300 °C was observed. Oxygen mobility in these ceramics can be characterised with chemical diffusion coefficients (1-9) × 10-9 cm2 s-1 at 900 °C and pO2 = 1000-21,000 Pa.

Novel structural features and phase transition behaviour of (Sr1-xCax)TiO3: I. Neutron diffraction study

Superlattice reflections observed for the first time in the room temperature powder neutron diffraction patterns of SCT (Sr1-xCaxTiO3, x ≥ 0.12) are shown to arise due to tilting of TiO6 octahedra. Rietveld refi

Phase formation and dielectric phase transition in Ba1-xCaxTi0.6Zr0.4O3 solid solutions

Perovskite types Ba1-xCaxTi0.6Zr0.4O3 (with x=0.0-0.5) ceramics have been prepared through solid state reaction route. The room temperature XRD study suggests the compositions with x=0.0 and x=0.1 have single phase cubic symmetry. With further increase in Ca content, solid solution breaks and an orthorhombic CaTiO3 like phase is developed. The dielectric study on single phase compositions (x=0.0 and 0.1) reveals that the materials are of relaxor type and undergo a diffuse type ferroelectric phase transition. In the Ca containing composition higher transition temperature is observed than the pure BaTi0.6Zr0.4O3 materials. In the paraelectric region (above Tc) lower diffusivity is observed in the Ca containing composition. The strength of relaxation is calculated and found to be more in Ca containing material than that of pure BaTi0.6Zr0.4O3 composition.

Enhancement of photoluminescence and color purity of CaTiO3: Eu phosphor by Li doping

High color purity red phosphors of Ca1-3/2xEu xTiO3 and Ca1-2xEuxLi xTiO3 (0 a solid-state reaction method. The red emission photoluminescence intensity and color purity are enhanced by the incorporation of Li+ into CaTiO 3:Eu3+. The Li+ doping increases the emission probability from 5D0 state, increases photoluminescence intensity by 1.6 times, increases color purity to 92.1%, and shortens the decay time. With increasing Eu3+ and Li+ content, the color coordinates approach the ideal red chromaticity values, coming closer than commercial Y2O2S:Eu3+ red phosphor.

Microwave-assisted synthesis of defective Ca1-: XAgxTi1- yCoyO3with high photoelectrocatalytic activity for organic pollutant removal from water

CaTiO3 is considered to be one of the most promising catalysts for the degradation of organic pollutants, but its application is limited by the wide band gap and low catalytic activity. Element doping is an effective strategy to solve these problems. Herein, a novel CaTiO3 co-doped with Ag and Co (Ca1-xAgxTi1-yCoyO3) was synthesized by combining co-precipitation and the microwave hydrothermal method for the first time. The crystal structure, microstructure and light absorption of the material were systematically investigated. The results showed that Ca1-xAgxTi1-yCoyO3 had higher light absorption than pure CaTiO3, and the band gap was reduced to 2.78 eV. First-principles calculations indicated that Ag-Ca and Co-Ti tended to form donor-acceptor defect pairs in the doping process. These defect states not only enhanced the adsorption properties, but also could be used as carrier traps to optimize the dielectric properties of CaTiO3. In the photoelectrocatalytic system, with 0.01 g of catalyst, 98% of methylene blue in 100 mL solution (10 mg L-1) was degraded in 150 min. In addition, Ca1-xAgxTi1-yCoyO3 showed strong stability and excellent recyclability. The double ion co-doping technology will provide an effective strategy for improving the catalytic activity of traditional wide-band gap semiconductors. This journal is

Equilibrium phase relations of CaO–SiO2–TiO2 system at 1400 °C and oxygen partial pressure of 10?10 atm

The equilibrium phase relations and liquidus contours for the TiOx-containing oxide system in reducing atmospheres are of importance in understanding the smelting process of Ti-containing resources. Equilibrium - quenching experiments were conducted at 1400 °C for the CaO–SiO2-TiOx system at oxygen partial pressure of 10?10 atm controlled by a CO/CO2 gas mixture. The equilibrium phase compositions were analyzed by scanning electron microscopy - energy dispersive X-ray spectrometry. Perovskite, wollastonite, rutile, and silica were found to coexist with liquid oxide. The 1400 °C isotherm was then constructed for the CaO–SiO2-TiOx system, and the results revealed that lower oxygen partial pressures led to shrinkage of the rutile and wollastonite primary phase areas. The comparisons with the calculated sections by FactSage and MTDATA indicated that the oxygen partial pressure has an obvious influence on the molten phase domain and clear deviations from experimental data mainly existed in the primary phase field of rutile. Therefore, the present results are significant for updating the current TiOx-containing thermodynamic databases, giving a deeper understanding of the related high temperature processes.