Metallic Samarium Research Articles

Preparation of Sm2Fe17 alloy and induced mechanism by calciothermic reduction

SmF3 cannot be directly reduced to metallic samarium by calcium. In this work, we presented the thermodynamic calculation and preperation of Sm2Fe17 alloy by calciothermic reduction. The composition, crystal structure, elements distribution, chemical valence and induced mechanism of Sm2Fe17 alloy were analyzed and characterized by ICP, XRD, SEM, EDS and XPS. The results show that the feasibility of preparing Sm2Fe17 alloy by iron-induced SmF3 calciothermic reduction. The Sm and Fe component of SmFe alloy approximates the nominal composition of Sm2Fe17 alloy with 10% excess of SmF3 over the stoichiometry. The micrograph of the SmFe ingot exhibits fish-bone-like morphology and is composed of α-Fe, Sm2Fe17 and SmFe3 phases. The Sm and Fe elements of the samples demonstrate zero valency. Electrons from metallic Sm are drawn toward to the orbits of Fe and an Sm-Fe bond with ionic bond property is formed and being reduced by calcium to obtain Sm2Fe17 alloy.

Electrochemical and spectroscopic investigation of samarium in a neutral ligand based-ionic liquid

• Electrochemistry of samarium(III) in neutral ligand is reported. • FT-IR and Raman spectroscopy confirm the interaction of Sm 3+ with TMP via P O. • Charge transfer coefficient, α ~ 0.44 & D Sm3+ ~2.10 × 10 −7 cm 2 /s at 303 K. • Uniform Sm deposit obtained on glassy carbon and copper substrates. • Low-cost, stable neutral ligands are potential electrolytes for depositing Rare Earths. In the past few decades, ionic liquids have emerged as potential replacements to conventional electrolytes in many academic and industrial applications owing to their remarkable properties. However, poor solubility towards different metal salts exhibited by majority of the ionic liquids limits their capacity to obtain solutions with higher metal ion concentrations. Combining neutral ligand with ionic liquid has been suggested as a promising route to solve this issue. In this regard, we report the electrochemical and spectroscopic study of samarium(III) in trimethyl phosphate (TMP) ligand. Infrared and Raman spectroscopy probing of samarium tris bis(trifluoromethylsulfonyl) imide / trimethyl phosphate reveals that Sm(III) is coordinated to TMP molecule via oxygen atom of the P O group. Cyclic voltammetry at glassy carbon working electrode indicates that the reduction of samarium(III) to metallic samarium in TMP proceeds via two-steps involving quasi-reversible Sm(III)/Sm(II) and irreversible Sm(II)/Sm(0) charge transfer. Diffusion coefficient of Sm(III) was determined to be 2.10 × 10 −7 cm 2 /s. Compact deposits of samarium were obtained on glassy carbon and copper electrodes under potentiostatic deposition. EDS and elemental mapping analyses confirm uniform deposition of samarium throughout the electrode surface. XPS analysis confirmed that the samarium deposit is composed of metallic samarium coexisting with substantial amount of oxide form likely due to high reactivity of samarium with atmospheric oxygen. In this work, we report the spectroscopic analyses and voltammetric behaviour, and the electrodeposition of samarium using trimethyl phosphate and this strategy can be conveniently extended to other rare earths using similar neutral ligand based ionic liquids

Studying the Grain Structure of SmS Targets Manufactured under Variable Conditions

The grain structure of samarium sulfide (SmS) targets manufactured by pressing with or without subsequent high-temperature treatment by high-frequency current (HFC) at various pressures has been studied. The density of samples manufactured in various regimes was determined and the optimum technological conditions for obtaining high-quality SMS targets were selected. In particular, the HFC annealing upon pressing at 5 t/cm2 proved to be more effective than the analogous treatment at 4 t/cm2. It is established that the samples obtained by pressing at 5 t/cm2 without high-temperature HFC annealing contain significant amounts of unbound metallic samarium.

Исследование зеренной структуры мишеней SmS, полученных при различных условиях

The grains structure of samples of а SmS targets, obtained by pressing methods without and with the use of subsequent high-temperature processing by high- frequency currents (further HFC), under various pressure was investigated. The density of samples obtained under different conditions was determined. The optimal technological conditions for obtaining high-quality targets of a samarium monosulfide are determined: high-frequency annealing with pressing under pressure of 5t/cm 2 is more effective than high-frequency current annealing with pressing under pressure of 4 t/cm 2 . A significant content of unbound metallic samarium in samples obtained by pressing at 5 t/cm 2 but not subjected to high-temperature HFC annealing has been established.

Sm on CeO2(111): A Case for Ceria Modification via Strong Metal–Ceria Interaction

The growth, electronic structure and stability of Sm on ordered CeO2(111) thin films grown on Cu(111) were investigated by means of X-ray photoelectron spectroscopy (XPS), low energy electron diffraction, and scanning tunneling microscopy (STM). Metallic samarium was deposited on the CeO2(111) surface by thermal evaporation under ultrahigh vacuum conditions at room temperature. The XPS data suggest that metallic Sm is oxidized to Sm3+ upon the deposition of Sm on CeO2, accompanied by the reduction of Ce4+ to Ce3+. With increasing the Sm coverage, the concentration of Ce3+ increases monotonically. After depositing 6 ML of Sm, only Ce3+ is observed within the detection depth of XPS. The STM results indicate that Sm exhibits a two-dimensional growth on the CeO2(111) surface at low coverages. Annealing to higher temperatures leads to the agglomeration of Sm particles and concurrent diffusion of Sm into the ceria film. These results illustrate that Sm can modify both the electronic and structural properties of ceria.

Preparation and characterization of Sm2Fe17 alloy in LiF-CaF2-SmF3 molten salt

A suitable temperature range of Sm2Fe17 alloy formed only was chosen to investigate the electroreduction of Sm3+ on molybdenum and iron electrode in LiF-CaF2-SmF3 molten salt, which were studied by CV and SWV at different temperatures and concentrations of Sm3+. The reduction of Sm3+ to Sm0 on the iron electrode included two steps. Firstly, a soluble-soluble reaction appears at −0.33 V vs. Cr/Cr2O3 corresponds to the electroreduction of Sm3+ to Sm2+. The electroreduction of Sm3+ to Sm2+ is a reversible process, which is controlled by the diffusion of Sm3+ in the LiF-CaF2-SmF3 molten salt. Secondly, Sm2+ can be reduced at −0.78 V vs. Cr/Cr2O3 on the iron electrode in LiF-CaF2-SmF3 molten salt due to a lower activity of metallic samarium in the Sm2Fe17 alloy than that of samarium metal, and that makes samarium in Sm-Fe alloy more stable while that of Sm2+ could be not reduced by a molybdenum electrode. By experiment of potentiostatic electrolysis it was confirmed that the cathode product from LiF-CaF2-SmF3 melts at −1 V vs. Cr/Cr2O3 for 4 h is a thin layer metallic plate only composing Sm2Fe17 alloy.

Technical ceramics from samarium monosulfide for the thermal explosion and magnetron methods of production of SmS films

Physicotechnical foundations of producing technical ceramics from samarium monosulfide were developed. The stable daltonide-type compound SmS forms a solid solution primarily within the range of anion structural vacancies Sm1 + xS1–x[ ]2x (x = 0–0.035) (1500°С). In the Sm–S–O system, the compound SmS is in equilibrium with the Sm3S4 and Sm2O2S phases. The surface layer of bulk samples and films of SmS contains the phases Sm3S, Sm2O2S, and xSm2SO4 · (1–x)Sm2O3. Samarium sulfide is thermally hydrolyzed (>300°C) and oxidized (>220°C) to form the Sm3S4 and Sm2O2S phases. In synthesizing samarium monosulfide from elements by an ampule method, addition of a 15–20% excess of metallic samarium to the initial mixture affords SmS in more than 95 mol % yield. The contents of the equilibrium impurities Sm3S4 and Sm2O2S are minimized. Technical ceramics based on SmS was obtained as sintered pellets 50 and 75 mm in diameter with a compressive strength of 45 MPa, a flexural strength of 1.6 MPa, and a density of 4.89 g/cm3. The rate of SmS film sputtering from a ceramic target on a NanoFab-100 platform under the optimal sputtering conditions (390 V, 150 W) was 1 A/s. A SmS powder containing particles of 90–120 μm in size was used for thermal explosion spraying of semiconductor thermal sensors shaped as cubes with a side length of 5 and 10 mm.

Microstructure of an Ingot of Sm2Fe17 Intermetallic and its Homogenization

The phase composition and microstructure of Sm – Fe alloys obtained by vacuum induction melting of the elements are studied near the stoichiometry of Sm2F17 by the methods of scanning electron microscopy, local microanalysis and x-ray analysis. The possibility of coherent junction of all the phase components of an ingot is analyzed with the help of representation of the crystal structures of all intermetallics of the Sm – Fe system in terms of coordination polyhedrons. It is shown that long-term annealing at a high temperature (for 30 h at 1150°C) does not remove from the structure of the ingot the regions of metallic samarium formed due to the peritectic type of solidification of the Sm2Fe17 intermetallic.

Preparation of High Purity Rare Earth Metals of Samarium, Ytterbium and Thulium

Abstract High purity rare earth metals, including samarium, ytterbium and thulium, were prepared by vacuum reduction-distillation of each rare earth oxide with lanthanum metal. The results show that the rare earth metals of samarium and ytterbium with 4N-purity are obtained by direct vacuum reduction-distillation, and their purity is 99.99 wt% and 99.993 wt%, respectively, with respect to 75 impurities. There is a high concentration of reductant in thulium metal due to the higher reaction temperature and lower distillation velocity ratio of metallic thulium to lanthanum, so that the sublimation purification with lower temperature and high vacuum is needed. The purified thulium can reach a high purity of 99.995wt% with respect to 75 impurities. Therefore, the preparation of high purity reductant of lanthanum metal, especially of total amount control of metallic impurities, is the key step to obtain 99.99%-purity rare earth metallic samarium, ytterbium and thulium

Lattice dynamics of the rare-earth element samarium

The lattice dynamics of samarium is determined by in situ low-temperature nuclear inelastic scattering on a single crystalline (0001)Sm film, a polycrystalline Sm foil, and by first-principles theory. The ab initio calculated phonon dispersion relations and phonon density of states for the Sm-type structure and the double hexagonal-close-packed (dhcp) lattice, characteristic for light lanthanides, are compared. The dhcp unit cell, which is a factor of 2.24 smaller in height, exhibits more pronounced vibrational anisotropy in comparison to the Sm-type structure. The analysis reveals a minor influence of the spin-orbit coupling in the Sm atom on the lattice dynamics. A broadening of the longitudinal peak, not found in the calculations, suggests the influence of electron correlations on lattice dynamics in metallic samarium.

Diiodomethane: A Versatile C1 Building Block

Diiodomethane, better known as methylene iodide, is a dense (3.325 g/mL at 25˚C), light-sensitive, pale-yellow liquid. Because of its high density, it is used by the gemo­logical industry to determine the density of minerals.[1] Being such an interesting compound, diiodomethane is a versatile C1 building block, which can be used to form carbon–carbon and carbon–heteroatom bonds. It is an easy-to-handle compound and can be used in a wide number of different reactions such as epoxidation,[2] diazotization,[3] iodomethylation,[4] cyclopropanation,[5] alkene reduction,[6] and sigmatropic rearrangement.[7] In the presence of metallic samarium, the air-sensitive samarium diiodide (SmI2) is formed in situ; this is cheaper than buying samarium diiodide.[8]

High-temperature studies of the magnetic susceptibility of samarium and the Al2Sm compound

The magnetic susceptibility of metallic samarium and the Al2Sm intermetallic compound has been experimentally studied by the Faraday method in the temperature range of 300–1800 K. It has been shown that the temperature dependences of the magnetic susceptibility of Sm and Al2Sm in a crystalline state can be described in the framework of Van Vleck paramagnetism theory taking into account variable valence and the contribution from the conduction electrons. Using this theoretical interpretation of the data, the effective valence of samarium in the metallic state and in the Al2Sm intermetallic compound has been estimated as a function of the temperature.

ChemInform Abstract: Metallic Samarium Promoted Self‐Coupling of Baylis—Hillman Adducts to Functionalized 1,5‐Hexadienes in the Presence of I2/ClCO2Et/BiCl3 System.

ChemInform Abstract: Metallic Samarium Promoted Self‐Coupling of Baylis—Hillman Adducts to Functionalized 1,5‐Hexadienes in the Presence of I₂/ClCO₂Et/BiCl₃ System.

ChemInform Abstract: Reactions of Carbonyl Compounds with Benzyl Chloromethyl Ether of Diiodomethane in the Presence of Samarium(II) Iodide or Metallic Samarium. New Routes to 1,2-Diols, Iodohydrins and Cyclopropanols.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform Abstract: Metallic Samarium Promoted Reductive Dimerization Cyclization of gem-Diactivated Alkenes, Reductive Debromination of vic-Dibromides, and Reduction of Sodium Alkyl Thiosulfates in Aqueous Media.

Abstract In saturated NH 4 Cl (ap.)-THF solution at room temperature, metallic samarium promoted reductive dimerization cyclization of gem -diactivated alkenes, reductive debromination of vic -dibromides, and reduction of sodium alkyl thiosulfates occur to afford corresponding functionalized cyclopentenes, ( E )-alkenes, and disulfides, respectively in good yield. Only sub-stoichiometric quantities of samarium are employed in the former reactions and the trans - or trans,trans -form isomer is the majority product of the polysubstituted cyclopentene products.

ChemInform Abstract: Diastereoselective Allylation and Alkylation of Optically Active Imines with Metallic Samarium and a Catalytic Amount of Iodine.

Abstract Barbier-type allylation and alkylation of optically active imines such as N -benzylidenevalinol methyl ether was performed with metallic samarium, a catalytic amount of iodine, and allyl or alkyl halides. This reaction proceeded in a highly diastereoselective manner in THF at room temperature.

Metallic Samarium Promoted Self-Coupling of Baylis-Hillman Adducts to Functionalized 1,5-Hexadienes in the Presence of the I2/ClCO2Et/BiCl3 System

A facile strategy for the self-coupling of Baylis-Hillman adductsto functionalized 1,5-hexadienes has been described. Promoted bythe Sm/I 2 /ClCO 2 Et/BiCl 3 system,the present method allows for the conversion of MBH adducts to theircorresponding 1,5-hexadienes.

Synthesis of C,N‐Diaryl Nitrones from the Reduction of Nitroarene with Aromatic Aldehydes Promoted by Metallic Samarium.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Sm/TiCl4 (cat.) system-mediated intermolecular and intramolecular reductive coupling reactions of ketones with esters

Sm/TiCl4 system could well integrate the high reactivity of samarium(II) and high deoxygenation capacity of low valent titanium within one system. In this paper, the intermolecular and intramolecular reductive coupling reactions of ketones with esters mediated by metallic samarium (Sm) and a catalytic amount of titanium tetrachloride (TiCl4) were successfully developed. A series of substituted ketones and cyclic β-keto-esters were prepared in moderate to good yields under reflux and neutral conditions.

Synthesis of C, N-diaryl Nitrones from the Reduction of Nitroarene with Aromatic Aldehydes Promoted by Metallic Samarium

A mild and facile reduction of nitroarene with aromatic aldehydes promoted by metallic samarium to C, N-diaryl nitrones in moderate yields has been developed.