Cs Compounds Research Articles

Release of <sup>137</sup>Cs into the gas phase during the interaction of <sup>137</sup>Cs compounds with molten lead

The release of137Cs into an Ar flowduring the interaction of137CsI and137CsOH—137Cs2CO3with molten lead at a temperature of ~852 Kwas studied.During the heating of Pb0with137CsI,137CsOH—137Cs2CO3, and137CsI—137CsOH—137Cs2CO3, from 2 to 8% of137Cs can pass into the gas flow. Based on the distribution of137Cs between the elements of the gas purification system, it was concluded that the chemical and disperse composition of compounds containing137Cs in the gas phase is quite heterogeneous. Volatile137Cs compounds formed upon heating137CsI,137CsOH—137Cs2CO3, and137CsI—137CsOH—137Cs2CO3with Pb0in a gas flow at ~852 K can contain both charged aerosols and aerosols without electric charge.

Interaction of CsOH with structural steel 316L and simulated products of the steel-cladding reaction under assumed conditions relevant for the accident at the Fukushima Dai-Ichi Unit 2 and 3

A high radiation dose rate under the shield plugs of the Units 2 and 3 reactors at the Fukushima Dai-Ichi Nuclear Power Station (1F), raised an important question on volatile radioactive Cs migration, adsorption and retention on various structural materials during the accident. The high dose rate interferes with decommissioning work. The purpose of this study is to present basic knowledge on contamination mechanisms of a BWR reactor structural materials and post-accident debris by Cs compounds to help decommissioning companies consider the ways of decontamination and debris handling during 1F debris retrieval. Having this goal, a series of tests on CsOH contamination mechanism under assumed accident conditions for Units 2 and 3 was performed. The results may improve the accuracy of estimating the situation inside the reactor from the perspectives of accident analysis and materials’ properties. The test temperature and compounds were chosen based on the probable accident scenario. In particular, Cs adsorption was checked using preoxidized 316L stainless steel, a product of control blade degradation (steel-B4C eutectic) and a product of steel-channel box and cladding interaction (Zr-Fe based multiphase material). Penetration ability of Cs into the oxidized and metallic layers of materials was evaluated. CsOH most probable adsorption temperature range and new Cs containing phases’ formation temperature range were followed.

Seven-Membered Cyclic Diamidoalumanyls of Heavier Alkali Metals: Structures and C-H Activation of Arenes.

Like the previously reported potassium-based system, rubidium and cesium reduction of [{SiNDipp}AlI] ({SiNDipp} = {CH2SiMe2NDipp}2) with the heavier alkali metals [M = Rb and Cs] provides dimeric group 1 alumanyl derivatives, [{SiNDipp}AlM]2. In contrast, similar treatment with sodium results in over-reduction and incorporation of a formal equivalent of [{SiNDipp}Na2] into the resultant sodium alumanyl species. The dimeric K, Rb, and Cs compounds display a variable efficacy toward the C-H oxidative addition of arene C-H bonds at elevated temperatures (Cs > Rb > K, 110 °C) to yield (hydrido)(organo)aluminate species. Consistent with the synthetic experimental observations, computational (DFT) assessment of the benzene C-H activation indicates that rate-determining attack of the Al(I) nucleophile within the dimeric species is facilitated by π-engagement of the arene with the electrophilic M+ cation, which becomes increasingly favorable as group 1 is descended.

Temperature dependence of Cs release during oxidation of Cs-loaded graphite

As one of potential treatments for irradiated graphite (i-graphite) waste, the oxidation method has been attracting more concern due to features of high treating efficiency and significant volume reduction. The release of fission products during oxidation is of great significance for further off-gas decontamination procedures. Focusing on the release behavior of volatile cesium (Cs), Cs-loaded graphite was prepared by impregnation in this work followed by definite distribution and chemical speciation analyzing. Results showed that the increasing temperature and humidity during the oxidation were evidenced to promote the release of Cs compounds, and the chemical speciation of released compounds was prominently dependent on oxidizing temperature. When the oxidation temperature was around 700 °C, Cs2O was predominately released with the morphology of spherical particles. When the oxidation temperature was increased to 900 °C, the predominant releasing composition turned to Cs2CO3 with morphologies of both spherical particles and nanorod-like shapes. The different predominant releasing chemical compositions at different temperatures mainly resulted from the kinetics of graphite oxidization and temperature synergistically. These findings will provide theoretical foundations to the environmental evaluation of i-graphite thermal oxidation.

Charge Transport Properties of a Series of Metal Quinolates Utilising Dispersion-Corrected Density Functional Theory

The electronic and charge transport properties of Metal-Quinolates (Metal = Li, Na, K, Rb and Cs) compounds are theoretically investigated using AustinFrisch-Petersson functional with dispersion (APFD) corrected density functional theory (DFT). The calculated energy gap between highest occupied molecular orbital and lowest unoccupied molecular orbital ranges from 3.40 eV for LiQ to 0.93 eV for CsQ. The ionisation potential, electron affinity and chemical hardness of the compounds are calculated. We found that the electron hopping rate, kelectron of CsQ is around 150 times greater than LiQ. We suggest that CsQ is the most efficient charge injecting or transport material for organic light-emitting diodes (OLEDs). Dimer formation is desirable with all M-Quinolate with different electronic structures and (CsQ)2 dimer shows the lowest dimerisation energy.

Analysis of XGaO3 (X = Ba and Cs) cubic based perovskite materials for photocatalytic water splitting applications: a DFT study

Energy conversion has become an important technology for meeting energy production and consumption in the modern era. Water splitting and solar cell technologies are projected to close the gap between demand and consumption. Therefore, XGaO3 (X = Ba and Cs) compounds having characteristics i.e., electrical, optical, mechanical, and structural are depicted by using a density functional theory (DFT) based CASTEP software with ultrasoft pseudo-potential plane-wave and Generalized Gradient Approximation and Perdew Burke Ernzerhof exchange correlation functional (GGA-PBE). According to the findings, all of these compounds have a cubic “pm3m” structure with space group 221. The CsGaO3 and BaGaO3 have direct and indirect band gaps, with respect to electronic band-structure recreations. Density of states like total density of states (TDOS) and partial density of states (PDOS) commend the extent of localization of electrons in numerous bands. The optical properties of these compounds are explored by adjusting dispersion curve/relation for theoretical dielectric function (DF) scale to the corresponding peaks. As a result, these materials could be used to consume light in the visible zone via photo catalysis. CsGaO3 in combination with BaGaO3 can produce effective results, so these compounds have a remarkable potential application for sensing and water splitting.

Cs incorporation via sequential deposition for stable and scalable organometal halide perovskite solar cells

In this study, uniform Cs distribution in an organometal halide perovskite (OHP) film was achieved via sequential deposition method entailing the dissolution of Cs compounds in dimethyl formamide (DMF) with inorganic components, as opposed to using isopropyl alcohol with organic components, and the thermal stability and crystallinity of the OHP film were enhanced by improving the structural stability through Cs incorporation. Additionally, the device performance and thermal stability of OHP solar cells were enhanced by Cs incorporation, which led to fewer defect sites and the suppression of defect generation in OHP films, as confirmed by optical and electrical analysis, improving the overall film quality. The sequential deposition method was more amenable to scaling up than the anti-solvent assisted one-step spin-casting method, as demonstrated by the sequential deposition of the OHP film uniformly over a substrate with size of 8 cm × 8 cm. The uniformly sequentially deposited OHP film was used to create a large-area 1 cm 2 OHP solar cell, which exhibited a high power conversion efficiency (PCE) of 16.77%. Further scalability of the sequentially deposited OHP solar cell was confirmed by highly uniform device performances by three cells on a single substrate with a negligible PCE standard deviation of 0.94%. • The uniform Cs distribution in OHP film is achieved via sequential deposition. • The thermal stability of the OHP film increased through Cs incorporation. • The performance and stability of the PeSCs is improved. • Uniform OHP film with large size is successfully fabricated by sequential deposition. • A p-i-n PeSCs with a size of 1 cm 2 was successfully fabricated.

Gas-Phase Conversion of Uranium-Containing Compounds of Cs and Sr in the Nitrating Atmosphere

Gas-Phase Conversion of Uranium-Containing Compounds of Cs and Sr in the Nitrating Atmosphere

Low-energy optical properties of the nonmagnetic kagome metal CsV3Sb5

Temperature-dependent reflectivity measurements on the kagome metal CsV$_3$Sb$_5$ in a broad frequency range of $50-20000$ cm$^{-1}$ down to $T$=10 K are reported. The charge-density wave (CDW) formed below $T_{\rm CDW}$ = 94 K manifests itself in a prominent spectral-weight transfer from low to higher energy regions. The CDW gap of 60-75 meV is observed at the lowest temperature and shows significant deviations from an isotropic BCS-type mean-field behavior. Absorption peaks appear at frequencies as low as 200 cm$^{-1}$ and can be identified with interband transitions according to density-functional calculations. The change in the interband absorption compared to KV$_3$Sb$_5$ reflects the inversion of band saddle points between the K and Cs compounds. Additionally, a broader and strongly temperature-dependent absorption feature is observed below 1000 cm$^{-1}$ and assigned to a displaced Drude peak. It reflects localization effects on charge carriers.

Lab-scale and pore-scale study of low-permeability soil diffusional tortuosity

Diffusion coefficients for Na+ was measured in low-permeability samples (diameter of 3 cm and average length of 7 cm) from the deep disposal site of the Siberian Chemical Combine (SCC) using the end-diffusion technique. The direction of diffusion was perpendicular to the direction of bedding. Special equipment was designed and constructed for the experiment. Two types of concentration observations were used. For non-sorbing Na+, EC sensors and the length distribution of sorbed elements were used. The synthetic solution used in the experiments was a model of the low-activity contaminant of the SCC and consisted of NaNO3 (25 g/L) and nitrate compounds of Cs+, Ni2+, Co2+, and Sr2+ (100 mg/L each). The measured values of the effective diffusion coefficients De for Na+ from 1.92 × 10−11 to 1.70 × 10−10 m2/s. The microstructure was studied with X-ray microtomography for the same cores. Image shooting was performed on undisturbed microsamples with a size of 0.913 mm (7003 vox). Spatial correlation analysis was performed after the binarization of each obtained 3-D structure. This analysis showed that the spatial correlation scale of the indicator variogram is considerably smaller than the microsample length. Then, a numerical simulation of the Laplace equation with binary coefficients for each microsample was performed. The results were analysed in the form of a plot of the tortuosity versus the porosity. Pore-scale simulations show a nonlinear decrease in the tortuosity with decreasing porosity. Exponential values in the range between 1.8 and 2.4 were found by fitting this graph with Archie's model. Anisotropic tortuosity is also detected in the horizontal and vertical directions. The diffusion coefficients of non-sorbing Na+ measured in this study agree with those of the pore-scale diffusion simulation of the microtomography data.

Metamagnetoelectric transitions-enhanced multicaloric effect in multiferroics A2Cu2Mo3O12 (A=Rb and Cs) quantum spin chain

The multicaloric properties of multiferroic A 2 Cu 2 Mo 3 O 12 (A = Rb and Cs) compounds are theoretically investigated through a frustrated one-dimensional spin ribbon chain of CuO 2 . The system submitted to external magnetic and electric field constraints grants the particular interest of metamagnetoelectric effect arising at relatively low temperatures. The isentropes of Rb 2 Cu 2 Mo 3 O 12 and Cs 2 Cu 2 Mo 3 O 12 exhibit about four major sharper dips by lowering temperature. This highlights four meta-transitions points which in turn are simultaneously metamagnetic and metaelectric, and therefore conveniently treated as metamagnetoelectric transitions. In the vicinities of the metamagnetoelectric transitions and in the quantum critical region, the thermal entropies are relatively large, which thus results in metamagnetoelectric transitions-enhanced multicaloric effect. Furthermore, this enhancement appears in the cooling process where the adiabatic magnetic and electric cooling rates diverge in the vicinity of the metamagnetoelectric transition points indicating the prominent low-temperature multicaloric effect. It is then certain that by making use of such large magnetoelectric coupling at metamagnetoelectric transition regions, the refrigerating efficiency of multiferroic materials will be further improved. • The multicaloric properties of multiferroic A 2 Cu 2 Mo 3 O 12 (A = Rb and Cs) compounds are theoretically investigated. • The system submitted to external magnetic and electric field constraints exhibits the metamagnetoelectric effect. • The metamagnetoelectric transitions increase the thermal entropy, leading to an enhancement of the multicaloric effect. • The adiabatic cooling rates at the metamagnetoelectric transitions emphasize prominent low-temperature multicaloric effect.

Instantaneous Ex Situ Mineral Carbonation Relevant to Alkali Metals in Clay Nanoparticles

Carbon recycling reusing emitted carbon dioxide (CO2) as raw materials is nowadays recognized as a concept ahead of CO2 capture and storage for controlling its emission to the air. Here, recently discovered alkali-metal-based instantaneous ex situ mineral carbonation under ambient conditions is studied for saponite clay nanoparticles. The cationic concentration of Cs+ is varied for seeking the possibility of reusing Cs-contaminated soil in view of carbon recycling. The ex situ mineral carbonation dominantly occurring at the interior surfaces of 10 Å open spaces formed by overlapped nanosheets increases with increasing the Cs concentration up to 0.580 mmol g–1 due to the enlargement of the surface area. The ability of the ex situ mineral carbonation, however, deteriorates with further increasing to 0.585 mmol g–1 since the 10 Å open spaces are effectively occupied by Cs compounds as Cs2O reducing their fraction. The present findings of the ex situ mineral carbonation relevant to the cationic concentration imply that the practical soil associated with a Fukushima nuclear accident can stabilize CO2 without energy consumption as well as chemical solution.

Metamagnetoelectric effect in multiferroics A2Cu2Mo3O12 (A=Rb and Cs) quantum spin chain

The magnetoelectric and thermodynamic properties of multiferroic A2Cu2Mo3O12 (A=Rb and Cs) compounds are investigated through the theoretical laboratory of a frustrated one-dimensional spin chain of CuO2 ribbon where inter-chain couplings are ignored. The general framework is built under external magnetic and electric field constraints with additional anisotropies. The field scans of magnetoelectric properties highlight a set of interdependent meta-transition giving birth to the metamagnetoelectric effect. Those meta-transitions are likewise reported by typically measured field dependencies of entropy and further of heat capacity that reveals a breakdown of temperature-energy dependence during meta-transitions. The temperature-energy dependence breakdown vanishing reported for high temperature emphasizes the metamagnetoelectric state death beyond relatively low-temperature values. Furthermore, large temperature-fields dependencies are noticed except for critical values where meta-transitions are occurring in the investigated A2Cu2Mo3O12 compounds.

Synthesis and Characterization of the Tetrafluoridochlorates(III) A[ClF4] (A = K, Rb, Cs)

Single‐crystalline tetrafluoridochlorates(III) A[ClF4] (A = K, Rb, Cs) were synthesized from solvolysis reactions of alkali metal fluorides in liquid chlorine trifluoride. The structures were examined by means of single‐crystal X‐ray diffraction. K[ClF4] crystallizes in the K[BrF4] structure type, whereas the Rb and Cs compounds crystallize in the Li[AuF4] structure type. The compounds were further characterized by Raman and IR spectroscopy. Solid‐state quantum‐chemical calculations with hybrid density functional methods reproduced the experimental structures and enabled the interpretation of the experimental Raman and IR spectra.

FIRST-PRINCIPLES STUDY OF MAGNETISM AND HALF-METALLIC PROPERTIES OF THE D0 QUATERNARY HEUSLER ALLOYS BANYO (Y = K, RB AND CS)

First-principles theory was applied to investigate the electronic, elastic, magnetic, and half-metallic behaviors of the newly designed quaternary Heusler compounds BaNYO (Y = K, Rb and Cs) without 3d transition metal elements. However, elastic properties show that our compounds are ductile and anisotropic. The calculated results show that our compounds are half-metallic with an integer magnetic moment of 2.00 µB at the equilibrium lattice parameter, with 100 % spin polarization around the Fermi level, which follows the famous Slater-Pauling rule, Mtot =16 − Zt, Mtot is the total magnetic moment and Zt is the total number of valence electrons. Based on its equilibrium and strained lattice constants, the magnetic and half-metallic behaviors of this compound have been discussed in detail. Large half-metallic gaps of BaNYO (Y = K, Rb and Cs) compounds of 0.95, 0.90 and 0.85 eV, respectively have been found in our work, which is nearly larger than any previous study. Furthermore, the calculated negative formation energy and cohesive energy indicate that these two alloys have good chemical stability. This theoretical investigation provides further insight into the application of BaNYO compounds as spintronic materials.

Copper hydroselenite nitrates (A+NO3)n[Cu(HSeO3)2] (A=Rb+, Cs+and Tl+,n=1, 2) related to Ruddlesden – Popper phases

AbstractThree new layered copper hydrogen selenite nitrates, (ANO3)[Cu(HSeO3)2] (A = Cs, and Tl), and (RbNO3)2[Cu(HSeO3)2] have been prepared via isothermal evaporation of concentrated nitric acid solutions. The Tl and Cs compounds adopt a motif related to previously known (NH4Cl)[Cu(HSeO3)2]; the structure of the Rb compound represents a new structure type. The structures of (ANO3)[Cu(HSeO3)2] (A = Cs, Tl), (RbNO3)2[Cu(HSeO3)2], and (NH4NO3)3[Cu(HSeO3)2] form a unique homological series distantly related to Ruddlesden – Popper series of layered perovskites.

Influence of the Presence of Different Alkali Cations and the Amount of Fe(CN)6 Vacancies on CO2 Adsorption on Copper Hexacyanoferrates.

The CO2 adsorption on various Prussian blue analogue hexacyanoferrates was evaluated by thermogravimetric analysis. Compositions of prepared phases were verified by energy-dispersive X-ray spectroscopy, infra-red spectroscopy and powder X-ray diffraction. The influence of different alkali cations in the cubic Fm3m structures was investigated for nominal compositions A2/3Cu[Fe(CN)6]2/3 with A = vacant, Li, Na, K, Rb, Cs. The Rb and Cs compounds show the highest CO2 adsorption per unit cell, ~3.3 molecules of CO2 at 20 °C and 1 bar, while in terms of mmol/g the Na compound exhibits the highest adsorption capability, ~3.8 mmol/g at 20 °C and 1 bar. The fastest adsorption/desorption is exhibited by the A-cation free compound and the Li compound. The influence of the amount of Fe(CN)6 vacancies were assessed by determining the CO2 adsorption capabilities of Cu[Fe(CN)6]1/2 (Fm3m symmetry, nominally 50% vacancies), KCu[Fe(CN)6]3/4 (Fm3m symmetry, nominally 25% vacancies), and CsCu[Fe(CN)6] (I-4m2 symmetry, nominally 0% vacancies). Higher adsorption was, as expected, shown on compounds with higher vacancy concentrations.

Chromatographic analysis of the traces of 2-chlorobenzalmalononitrile with passive adsorption from the headspace on Tenax TA and Carbotrap 300

The main purpose of the presented research was to check if CS agent (Chlorobenzylidenomalononitrile CAS 2698-41-1) can be separated from the forensic samples using passive adsorption from the headspace on the adsorption tubes and, if so, what are the optimal conditions of this process. Two different adsorbents were checked (adsorption tubes filled with Tenax TA and adsorption tubes filled with Carbotrap 300). Three different packages (gastight bags by Ampac, Nylon bags by BVDA and twist-off jars) were tried and the temperature range checked was 30°C–105°C. This research demonstrated CS is not volatile enough to enter the headspace in a gaseous form, therefore it cannot be adsorbed regardless of adsorbent, package, and temperature, in the investigated temperature range. In all the samples a product of CS hydrolysis this is 2-chlorobenzaldehyde (CAS 89-98-5) was detected. The presence of 2-chlorobenzaldehyde maybe therefore used as an indirect proof that the investigated sample was in contact with CS compound. 2-chlorobenzaldehyde is much more effectively adsorbed on Tenax TA than on Carbotrap 300. The other conclusion from this part of the research is that twist-of glass jars and nylon bags are not entirely gas-tight and should not be used as a package on the adsorption stage.Methanol is usually used for the extraction of irritating compounds from the samples, therefore the stability of CS agent in methanolic solutions was investigated. The research demonstrated that CS is unstable in methanol and hydrolyze to 2-chlorobenzaldehyde. This is most probably because, in the HPLC grade methanol which was used, a small amount of water is present. The hydrolysis is slower if the solution is stored in an amber glass vial and much faster when stored in transparent vials.

Three new acid M+ arsenates and phosphates with multiply protonated As/PO4 groups.

The crystal structures of caesium dihydrogen arsenate(V) bis[trihydrogen arsenate(V)], Cs(H2AsO4)(H3AsO4)2, ammonium dihydrogen arsenate(V) trihydrogen arsenate(V), NH4(H2AsO4)(H3AsO4), and dilithium bis(dihydrogen phosphate), Li2(H2PO4)2, were solved from single-crystal X-ray diffraction data. NH4(H2AsO4)(H3AsO4), which was hydrothermally synthesized (T = 493 K), is homeotypic with Rb(H2AsO4)(H3AsO4), while Cs(H2AsO4)(H3AsO4)2 crystallizes in a novel structure type and Li2(H2PO4)2 represents a new polymorph of this composition. The Cs and Li compounds grew at room temperature from highly acidic aqueous solutions. Li2(H2PO4)2 forms a three-dimensional (3D) framework of PO4 tetrahedra sharing corners with Li2O6 dimers built of edge-sharing LiO4 groups, which is reinforced by hydrogen bonds. The two arsenate compounds are characterized by a 3D network of AsO4 groups that are connected solely via multiple strong hydrogen bonds. A statistical evaluation of the As-O bond lengths in singly, doubly and triply protonated AsO4 groups gave average values of 1.70 (2) Å for 199 As-OH bonds, 1.728 (19) Å for As-OH bonds in HAsO4 groups, 1.714 (12) Å for As-OH bonds in H2AsO4 groups and 1.694 (16) Å for As-OH bonds in H3AsO4 groups, and a grand mean value of 1.667 (18) Å for As-O bonds to nonprotonated O atoms.

An experimental investigation of influencing chemical factors onCs-chemisorption behavior onto stainless steel

ABSTRACT A more accurate cesium hydroxide (CsOH)-chemisorption model is required to improve the estimation of the Cs distribution in Fukushima Daiichi Nuclear Power Station by severe-accident (SA) analysis codes. The current CsOH-chemisorption model incorporated in SA analysis codes was developed with insufficient information of chemical factors such as H2/H2O ratio, concentration of chemically affecting elements, heating time, and surface condition of the stainless steel (SS). Therefore, we have conducted experimental tests for CsOH-chemisorption onto SS type-304 (SS304) in order to examine the effect and dependence of such chemical factors on the CsOH-chemisorption behavior in detail. It was found that the first-order surface-reaction rate constant was influenced by not only temperature, as already known, but also H2/H2O ratio, CsOH concentration in the gas phase, and silicon content in SS304. Such chemical factors should be considered for the construction of the improved CsOH-chemisorption model. Another important finding is that the chemisorption behavior at lower temperatures, around 873 K, could differ from those above 1073 K. Namely, Cs–Fe–O compounds would form as the main chemisorbed Cs compounds at 873 K while Cs–Si–Fe–O compounds at more than 1073 K.