Europium - Wikipedia. Europium, 6. 3Eu. General properties. Pronunciationew- ROH- pee- əm. Appearancesilvery white, with a pale yellow tint; [1] but rarely seen without oxide discoloration. Standard atomic weight(Ar, std)7. Europium in the periodic table. Atomic number(Z)6. Free Download Analytical Chemistry, Organic Chemistry, Physical Chemistry, Food Chemistry and Biochemistry Books in portable document format (.pdf). Europium is a ductile metal with a hardness similar to that of lead. . It crystallizes in a body-centered cubic lattice.Some properties of europium are strongly. Group, periodgroup n/a, period 6. Blockf- block. Element category lanthanide. ![]() Electron configuration[Xe] 4f. Electrons per shell. Physical properties. Phase(at STP)solid. Melting point. 10. K (8. 26 °C, 1. F)Boiling point. 18. K (1. 52. 9 °C, 2. F)Density(near r. Heat of fusion. 9. J/mol. Heat of vaporization. J/mol. Molar heat capacity. J/(mol·K)Vapor pressure. P (Pa)1. 10. 10. 01 k. T (K)8. 63. 95. 71. Atomic properties. Oxidation states. Electronegativity. Pauling scale: 1. Ionization energies. Gain an understanding of the latest advances in spectroscopy with INTRODUCTION TO SPECTROSCOPY.This proven book provides a systematic introduction to spect.J/mol. 2nd: 1. 08. J/mol. 3rd: 2. 40. J/mol. Atomic radiusempirical: 1. Covalent radius. 19. Miscellanea. Crystal structurebody- centered cubic (bcc). Thermal expansionpoly: 3. K) (at r. t.)Thermal conductivityest. W/(m·K)Electrical resistivitypoly: 0. Magnetic orderingparamagnetic[3]Magnetic susceptibility+3. Young's modulus. 18. GPa. Shear modulus. GPa. Bulk modulus. GPa. Poisson ratio. Vickers hardness. MPa. CAS Number. 74. History. Namingafter Europe. Discovery and first isolation. Eugène- Anatole Demarçay (1. Main isotopes of europium. Wikidata. Europium is a chemical element with symbol Eu and atomic number 6. It was isolated in 1. Europe.[5] It is a moderately hard, silvery metal which readily oxidizes in air and water. Being a typical member of the lanthanide series, europium usually assumes the oxidation state +3, but the oxidation state +2 is also common. All europium compounds with oxidation state +2 are slightly reducing. Europium has no significant biological role and is relatively non- toxic compared to other heavy metals. Most applications of europium exploit the phosphorescence of europium compounds. Europium is one of the least abundant elements in the universe; only about 6. Characteristics[edit]Physical properties[edit]. About 3. 00 g of dendritic sublimated 9. Oxidized europium, coated with yellow europium(II) carbonate. Europium is a ductile metal with a hardness similar to that of lead. It crystallizes in a body- centered cubic lattice.[6] Some properties of europium are strongly influenced by its half- filled electron shell. Europium has the second lowest melting point and the lowest density of all lanthanides.[6]Europium becomes a superconductor when it is cooled below 1.K and compressed to above 8.GPa. This is because europium is divalent in the metallic state,[7] and is converted into the trivalent state by the applied pressure. Arquitectura De Software Modelos Estructurales De Casa . In the divalent state, the strong local magnetic moment (J = 7/2) suppresses the superconductivity, which is induced by eliminating this local moment (J = 0 in Eu.Chemical properties[edit]Europium is the most reactive rare- earth element. It rapidly oxidizes in air, so that bulk oxidation of a centimeter- sized sample occurs within several days.[9] Its reactivity with water is comparable to that of calcium, and the reaction is. Eu + 6 H2. O → 2 Eu(OH)3 + 3 H2. Because of the high reactivity, samples of solid europium rarely have the shiny appearance of the fresh metal, even when coated with a protective layer of mineral oil. Europium ignites in air at 1. C to form europium(III) oxide: 4 Eu + 3 O2 → 2 Eu. O3. Europium dissolves readily in dilute sulfuric acid to form pale pink solutions of the hydrated Eu(III), which exist as a nonahydrate: [1. Eu + 3 H2. SO4 + 1. H2. O → 2 [Eu(H2. O)9]3+ + 3 SO2−4 + 3 H2. Eu(II) vs. Eu(III)[edit]Although usually trivalent, europium readily forms divalent compounds. This behavior is unusual to most lanthanides, which almost exclusively form compounds with an oxidation state of +3. The +2 state has an electron configuration 4f. In terms of size and coordination number, europium(II) and barium(II) are similar. For example, the sulfates of both barium and europium(II) are also highly insoluble in water.[1. Divalent europium is a mild reducing agent, oxidizing in air to form Eu(III) compounds. In anaerobic, and particularly geothermal conditions, the divalent form is sufficiently stable that it tends to be incorporated into minerals of calcium and the other alkaline earths. This ion- exchange process is the basis of the "negative europium anomaly", the low europium content in many lanthanide minerals such as monazite, relative to the chondritic abundance. Bastnäsite tends to show less of a negative europium anomaly than does monazite, and hence is the major source of europium today. The development of easy methods to separate divalent europium from the other (trivalent) lanthanides made europium accessible even when present in low concentration, as it usually is.[1. Isotopes[edit]Naturally occurring europium is composed of 2 isotopes, 1. Eu and 1. 53. Eu, with 1. Eu being the most abundant (5. While 1. 53. Eu is stable, 1. Eu was recently found to be unstable to alpha decay with half- life of 7. This value is in reasonable agreement with theoretical predictions. Besides the natural radioisotope 1. Eu, 3. 5 artificial radioisotopes have been characterized, the most stable being 1. Eu with a half- life of 3. Eu with a half- life of 1. Eu with a half- life of 8. All the remaining radioactive isotopes have half- lives shorter than 4. This element also has 8 meta states, with the most stable being 1. Eu (t. 1/2=1. 2. 8 hours), 1. Eu (t. 1/2=9. 3. 11. Eu (t. 1/2=9. 6 minutes).[1. The primary decay mode for isotopes lighter than 1. Eu is electron capture, and the primary mode for heavier isotopes is beta minus decay. The primary decay products before 1. Eu are isotopes of samarium (Sm) and the primary products after are isotopes of gadolinium (Gd).[1. Europium as a nuclear fission product[edit]Thermal neutron capture cross sections. Isotope. 15. 1Eu. Eu. 15. 3Eu. 15. 4Eu. Eu. Yield~1. 0low. Barns. 59. 00. 12. Europium is produced by nuclear fission, but the fission product yields of europium isotopes are low near the top of the mass range for fission products. Like other lanthanides, many isotopes, especially isotopes with odd mass numbers and neutron- poor isotopes like 1. Eu, have high cross sections for neutron capture, often high enough to be neutron poisons. Eu is the beta decay product of samarium- 1. Sm instead ends up as 1. Sm. 1. 52. Eu (half- life 1. Eu (half- life 8. Sm and 1. 54. Sm are non- radioactive, but 1. Eu is the only long- lived "shielded" nuclide, other than 1. Cs, to have a fission yield of more than 2. A larger amount of 1. Eu is produced by neutron activation of a significant portion of the non- radioactive 1. Eu; however, much of this is further converted to 1. Eu. 1. 55. Eu (half- life 4. Overall, europium is overshadowed by caesium- 1. Occurrence[edit]Europium is not found in nature as a free element. Many minerals contain europium, with the most important sources being bastnäsite, monazite, xenotime and loparite- (Ce).[2. Depletion or enrichment of europium in minerals relative to other rare- earth elements is known as the europium anomaly.[2. Europium is commonly included in trace element studies in geochemistry and petrology to understand the processes that form igneous rocks (rocks that cooled from magma or lava). The nature of the europium anomaly found helps reconstruct the relationships within a suite of igneous rocks. Divalent europium (Eu. Ca. F2). The reduction from Eu. Eu. 2+ is induced by irradiation with energetic particles.[2. The most outstanding examples of this originated around Weardale and adjacent parts of northern England; it was the fluorite found here that fluorescence was named after in 1. Production[edit]Europium is associated with the other rare- earth elements and is, therefore, mined together with them. Separation of the rare- earth elements is a step in the later processing. Rare- earth elements are found in the minerals bastnäsite, loparite- (Ce), xenotime, and monazite in mineable quantities. Bastnäsite is an orthophosphate mineral Ln. PO4 (Ln denotes a mixture of all the lanthanides except promethium), loparite- (Ce) is an oxide, and xenotime is a fluorocarbonate Ln. CO3. F. Monazite also contains thorium and yttrium, which complicates handling because thorium and its decay products are radioactive. For the extraction from the ore and the isolation of individual lanthanides, several methods have been developed. The choice of method is based on the concentration and composition of the ore and on the distribution of the individual lanthanides in the resulting concentrate. Recent functional near infrared spectroscopy based brain computer interface systems: Developments, applications and challenges. Kito H, Ryokawa A, Kinoshita Y, Sasayama D, Sugiyama N, Ogihara T, Yasaki T, Hagiwara T, Inuzuka S, Takahashi T, Genno H, Nose H, Hanihara T, Washizuka S, Amano N. Comparison of alterations in cerebral hemoglobin oxygenation in late life depression and Alzheimer’s disease as assessed by near- infrared spectroscopy. Behav Brain Funct.
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