The last rare earth element of the cerium subgroup - europium - just like its neighbors on the periodic table, is one of the most powerful absorbers of thermal neutrons. This is the basis for its use in nuclear technology and radiation protection technology.
As an anti-neutron protection material, element No. 63 is interesting because its natural isotopes 151 Eu and 153 Eu, absorbing neutrons, are converted into isotopes whose cross section for capturing thermal neutrons is almost as large.
Radioactive europium produced in nuclear reactors has been used to treat some forms of cancer.
Europium has gained importance as an activator of phosphors. In particular, yttrium oxide, oxysulfide and orthovanadate YV0 4, used to produce red color on television screens, are activated by micro-impurities of europium. Other phosphors activated by europium are also of practical importance. They are based on zinc and strontium sulfides, sodium and calcium fluorides, calcium and barium silicates.
It is known that attempts were made to alloy some special alloys with europium, separated from other lanthanides, in particular zirconium-based alloys.
Element No. 63 is not like other rare earth elements in every way. - the lightest of the lanthanides, its density is only 5.245 g/cm 3 . Europium has the largest atomic radius and atomic volume of all lanthanides. Some researchers also associate these “anomalies” in the properties of element No. 63 with the fact that of all the rare earth elements, europium is the least resistant to the corrosive action of moist air and water.
Reacting with water, europium forms a soluble compound Eu(0H) 2 *2H 2 0. It is yellow in color, but gradually turns white during storage. Apparently, further oxidation by atmospheric oxygen to Eu 2 0 3 occurs here.
As we already know, in compounds europium can be di- and trivalent. Most of its compounds are white, usually with a cream, pinkish or light orange tint. Compounds of europium with chlorine and bromine are photosensitive.
As is known, trivalent ions of many lanthanides can be used, like the Cr 3+ ion in ruby, to excite laser radiation. But of all of them, only the Eu 3+ ion produces radiation in the part of the spectrum perceived by the human eye. The europium laser beam is orange.
Origin of the name europium
Where the name of element No. 63 comes from is not difficult to understand. As for the history of the discovery, it was difficult and long to discover.
In 1886, the French chemist Demarsay isolated a new element from Samarp's earth, which was, apparently, not pure europium. But his experience could not be reproduced. In the same year, the Englishman Crookes discovered a new line in the spectrum of samarskite. Lecoq de Boisbaudran made a similar message six years later. But all the data about the new element were somewhat shaky.
Demarsay showed character. He spent several years isolating a new element from samarium earth and, having finally prepared (this was already in 1896) a pure preparation, he clearly saw the spectral line of the new element. Initially, he designated the new element with the Greek capital letter “sigma” - 2. In 1901, after a series of control experiments, this element received its current name.
Metallic europium was first obtained only in 1937.
Europium
EUROPIUM-and I; m.[lat. Europium] Chemical element (Eu), a silvery-white radioactive metal belonging to the lanthanides (obtained artificially; used in the nuclear and radio engineering industries).
europium(lat. Europium), a chemical element of group III of the periodic table, belongs to the lanthanides. Metal, density 5.245 g/cm 3, t pl 826°C. The name comes from “Europe” (part of the world). Neutron absorber in nuclear reactors, phosphor activator in color TVs.
EUROPIUMEUROPIUM (lat. Europium), Eu (read “europium”), chemical element with atomic number 63, atomic mass 151.96. Consists of two stable isotopes 151 Eu (47.82%) and 153 Eu (52.18%). Configuration of outer electronic layers 4 s 2
p 6
d 10
f 7
5s 2
p 6
6s 2
. The oxidation state in compounds is +3 (valence III), less often +2 (valence II).
Belongs to rare earth elements (cerium subgroup of lanthanides). Located in group III B, in the 6th period of the periodic table. The radius of the neutral atom is 0.202 nm, the radius of the Eu 2+ ion is 0.131 nm, and the Eu 3+ ion is 0.109 nm. Ionization energies 5.664, 11.25, 24.70, 42.65 eV. Electronegativity according to Pauling (cm. PAULING Linus) 1.
History of discovery
Europium was discovered by E. Demarsay in 1886. The element received its name in 1901 after the name of the continent. Europium metal was first obtained in 1937.
Being in nature
The europium content in the earth's crust is 1.310 -4%, in sea water 1.110 -6 mg/l. Part of the monazite minerals (cm. MONAZITE), loparita (cm. LOPARIT), bastnaesite (cm. BASTNESIT) and others.
Receipt
Metallic europium is obtained by the reduction of Eu 2 O 3 in vacuum with lanthanum or carbon, as well as by electrolysis of the EuCl 3 melt.
Physical and chemical properties
Europium is a silver-gray metal. Cubic lattice type a-Fe, A= 0.4582 nm. Melting point 826 °C, boiling point 1559 °C, density 5.245 kg/dm3.
In air, europium is covered with a film of oxides and hydrated carbonates. When heated slightly, it oxidizes quickly. When heated slightly, it reacts with halogens, nitrogen and hydrogen. Reacts with water and mineral acids at room temperature.
Eu 2 O 3 oxide has basic properties; it corresponds to the strong base Eu(OH) 3. The interaction of Eu and Eu 2 O 3, as well as the interaction of trivalent europium oxyhalides with lithium hydride LiH, produces europium (II) oxide EuO. The base Eu(OH) 2 corresponds to this oxide.
Application
It is used as a neutron absorber in nuclear technology, an activator of red phosphors used in color television. 155 Eu - in medical diagnostics.
encyclopedic Dictionary. 2009 .
Synonyms:See what “europium” is in other dictionaries:
- (symbol Eu), a silvery-white metal from the LANTHANIDE series, the softest and most volatile of them. It was first isolated in the form of an oxide in 1896. Europium is mined from the minerals monazite and bastnäsite. Used in the manufacture of color TV screens,... ... Scientific and technical encyclopedic dictionary
- (Europium), Eu, chemical element of group III of the periodic table, atomic number 63, atomic mass 151.96; belongs to rare earth elements; metal. Discovered by the French chemist E. Demarsay in 1901... Modern encyclopedia
- (lat. Europium) Eu, a chemical element of group III of the periodic table, atomic number 63, atomic mass 151.96, belongs to the lanthanides. Metal, density 5.245 g/cm³, melting point 826.C. The name comes from Europe (part of the world). Neutron absorber in... ... Big Encyclopedic Dictionary
- (Europium), Eu chemical. element of group III periodic. systems of elements, at. number 63, at. mass 151.96, part of the lanthanide family. Natural E. consists of isotopes with mass numbers 151 (47.82%) and 153 (52.18%). Electronic configuration of three... ... Physical encyclopedia
Noun, number of synonyms: 3 lanthanide (15) metal (86) element (159) ASIS Dictionary of Synonyms ... Synonym dictionary
europium- Eu Chemical element; belongs to lanthanides; in the form of oxide it is used in nuclear energy as a burnable absorber. [A.S. Goldberg. English-Russian energy dictionary. 2006] Topics energy in general Synonyms Eu EN europium ... Technical Translator's Guide
Europium- (Europium), Eu, chemical element of group III of the periodic table, atomic number 63, atomic mass 151.96; belongs to rare earth elements; metal. Discovered by the French chemist E. Demarsay in 1901. ... Illustrated Encyclopedic Dictionary
63 Samarium ← Europium → Gadolinium ... Wikipedia
- (lat. Europium), chemical. element III gr. period wild system, refers to the lanthanides. Metal, dense 5.245 g/cm3, melting point 826 0C. Name from Europe (part of the world). Neutron absorber in nuclear reactors, activator of phosphors in color. TVs... Natural science. encyclopedic Dictionary
- (prop.) chemical an element from the lanthanide family, symbol Eu (lat. europium); metal. New dictionary of foreign words. by EdwART, 2009. europium [Dictionary of foreign words of the Russian language
Books
- Popular library of chemical elements. In two books. Book 1. Hydrogen - Palladium,. The Popular Chemical Elements Library contains information about all the elements known to mankind. Today there are 107 of them, some of them obtained artificially. How different the properties are...
Europium - 63
Europium (Eu) is a rare earth metal, atomic number 63, atomic mass 152.0, melting point 826°C, density 5.166 g/cm3.
The name of the element, europium, which was discovered in its pure form in 1901, does not need an explanation of the origin of this name. In nature, there are no minerals with a sufficiently high content of europium, it is highly dispersed (monazite sand contains 0.002% of this element), but at the same time, europium in the earth’s crust is twice as much as silver, and gold is 250 times more.
It was possible to isolate europium compounds from minerals containing mixtures of salts of various lanthanides only in 1940, after lengthy research. The raw materials for the production of europium are minerals and man-made compounds: loparite (0.08%), eudialyte (0.95%), Khibiny apatite (0.7%), phosphogypsum from Khibiny apatite (0.6%), natural Tomtora concentrate ( 0.6%) (the percentage is indicated from the total content in the raw material).
Europium rare earth metal
Europium is a silvery-white metal, the lightest of the lanthanides, its density is 1.5 times less than that of iron. This metal is soft, similar in hardness to lead, and can be easily processed under pressure in an inert atmosphere.
Europium reacts with hydrogen and water, interacts with acids, but does not react with alkalis. In air it oxidizes well, forming an oxide film.
Of the radioactive isotopes of europium, europium-155 has been well studied (half-life about two years).
RECEIPT.
To isolate europium from a mixture of rare earth elements in minerals, chromatography and extraction methods are used to obtain either calcium fluoride or magnesium europium fluoride, from which metallic europium is then obtained.
Europium in metallic form is also obtained by reduction of its oxide Eu2O3, in a vacuum with the help of lanthanum or carbon, or by electrolysis of a melt of europium chloride EuCl3.
APPLICATION.
Europium is used relatively limitedly, due to its high cost, but in innovative technologies.
Nuclear power. The nuclei of europium atoms capture neutrons well, which is used in nuclear energy to use europium as a neutron absorber in regulating nuclear processes.
Lasers. Europium oxide is used to create solid-state and liquid lasers that generate laser radiation in the visible region of the spectrum (orange rays).
Astronomy. Flare phosphors, containing tiny fractions of a percent of europium, are used in astronomy in the infrared part of the spectrum to study the radiation of stars and nebulae.
Electronics. Modern microchips and memory devices are created, among other things, using europium.
Alloys and ceramics. Europium in ceramics is used to create superconductors, and its alloys are used in ferrous and non-ferrous metallurgy.
Hydrogen energy. To obtain thermal energy by thermo-chemical decomposition of water, europium oxide is used.
Other. Europium isotopes are used in medical diagnostics, in the creation of filters in environmental devices, and europium has begun to be used significantly for defense needs. In addition, the use of europium is under active study.
Flaw detection. The radioactive isotope of europium is used in lightweight portable devices for x-raying and checking the quality of thin-walled metal vessels. Gamma flaw detection based on europium isotopes is much more sensitive than flaw detection based on cesium and cobalt isotopes. To analyze minerals containing europium, europium salts are used that fluoresce under ultraviolet radiation. This method detects minute fractions of europium in the mineral under study.
Story
Being in nature
Place of Birth
Receipt
Metallic europium is obtained by the reduction of Eu 2 O 3 in vacuum with lanthanum or carbon, as well as by electrolysis of the EuCl 3 melt.
Prices
Europium is one of the most expensive lanthanides. In 2014, the price of europium metal EBM-1 ranged from 800 to 2000 US dollars per kg, and europium oxide with a purity of 99.9% was about 500 dollars per kg.
Physical properties
Europium in its pure form is, like the other lanthanides, a soft, silvery-white metal. It has unusually low density (5.243 g/cm3), melting point (826 °C) and boiling point (1440 °C) compared to its periodic table neighbors gadolinium and samarium. These values contradict the phenomenon of lanthanide compression due to the influence of the electronic configuration of the europium atom 4f 7 6s 2 on its properties. Since the f electron shell of the europium atom is half filled, only two electrons are provided for the formation of a metallic bond, the attraction of which to the nucleus is weakened and leads to a significant increase in the radius of the atom. A similar phenomenon is also observed in the ytterbium atom. Under normal conditions, europium has a body-centered cubic crystal lattice with a lattice constant of 4.581 Å. When crystallizing under high pressure, europium forms two more modifications of the crystal lattice. Moreover, the sequence of modifications with increasing pressure differs from the sequence in other lanthanides, which is also observed in ytterbium. The first phase transition occurs at pressures above 12.5 GPa, with europium forming a hexagonal crystal lattice with parameters a = 2.41 Å and c = 5.45 Å. At pressures above 18 GPa, europium forms a similar hexagonal crystal lattice with a more dense packing. Europium ions embedded in the crystal lattice of some compounds are capable of producing intense fluorescence, with the wavelength of the emitted light depending on the oxidation state of the europium ions. Eu 3+, almost regardless of the substance in whose crystal lattice it is embedded, emits light with wavelengths of 613 and 618 nm, which corresponds to an intense red color. On the contrary, the maximum emission of Eu 2+ strongly depends on the structure of the crystal lattice of the host substance and, for example, in the case of barium-magnesium aluminate, the wavelength of the emitted light is 447 nm and is in the blue part of the spectrum, and in the case of strontium aluminate (SrAl 2 O 4 :Eu 2+) wavelength is 520 nm and is in the green part of the visible light spectrum. At a pressure of 80 GPa and a temperature of 1.8 K, europium acquires superconducting properties.
Isotopes
Natural europium consists of two isotopes, 151 Eu and 153 Eu, in a ratio of approximately 1:1. Europium-153 has a natural abundance of 52.2% and is stable. The isotope europium-151 makes up 47.8% of natural europium. It has recently been discovered to have weak alpha radioactivity with a half-life of about 5 x 10 18 years, corresponding to about 1 decay per 2 minutes per kilogram of natural europium. In addition to this natural radioisotope, 35 artificial europium radioisotopes have been created and studied, among which the most stable are 150 Eu (half-life 36.9 years), 152 Eu (13.516 years) and 154 Eu (8.593 years). 8 metastable excited states were also discovered, among which the most stable are 150m Eu (12.8 hours), 152m1 Eu (9.3116 hours) and 152m2 Eu (96 minutes).
Chemical properties
Europium is a typical active metal and reacts with most nonmetals. Europium in the lanthanide group has the maximum reactivity. It oxidizes quickly in air; there is always an oxide film on the metal surface. Store in jars or ampoules under a layer of liquid paraffin or kerosene. When heated in air to a temperature of 180 °C, it ignites and burns to form europium (III) oxide.
4 E u + 3 O 2 ⟶ 2 E u 2 O 3 (\displaystyle \mathrm (4\ Eu+3\ O_(2)\longrightarrow 2\ Eu_(2)O_(3)) )
It is very active and can displace almost all metals from salt solutions. In compounds, like most rare earth elements, it exhibits predominantly an oxidation state of +3; under certain conditions (for example, electrochemical reduction, reduction with zinc amalgam, etc.) an oxidation state of +2 can be obtained. Also, when changing the redox conditions, it is possible to obtain an oxidation state of +2 and +3, which corresponds to an oxide with the chemical formula Eu 3 O 4. With hydrogen, europium forms non-stoichiometric phases in which hydrogen atoms are located in the interstices of the crystal lattice between the europium atoms. Europium dissolves in ammonia to form a blue solution, which is due, as in similar solutions of alkali metals, to the formation of solvated electrons.
Description
The electronic structure of the europium atom Eu I contains 63 electrons that filled 13 shells. The main term is the octet 8 S 7/2 of the configuration 4f 7 6s 2. When the s electron is excited, various terms of the 4f 7 6snl, 4f 7 5dnl and 4f 7 nl 2 configurations arise with high multiplicity (6,8,10) in the LS coupling, which form the spectrum. For the first time, the optical spectrum of the Eu I atom was studied by Russell H. and King A. (1934). Above the first ionization limit (45734.9 cm -1) there are levels of the 4f 7 5dnp configuration, above the second (47404.1 cm -1) there are unclassified levels. To date, the degree of study of Eu I is small; there are many unclassified levels and transitions.
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