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The use of europium. The chemical element europium: basic properties and applications




Europium

EUROPIUM-and I; m.[lat. Europium] A chemical element (Eu), a silver-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 system, belongs to the lanthanides. Metal, density 5.245 g / cm 3, t pl 826°C. Name from "Europe" (part of the world). Neutron absorber in nuclear reactors, phosphor activator in color televisions.

EUROPIUM

EUROPIUM (lat. Europium), Eu (read "europium"), a 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 electron layers 4 s 2 p 6 d 10 f 7 5s 2 p 6 6s 2 . The oxidation state in compounds is +3 (valency III), less often +2 (valence II).
Refers to rare earth elements (cerium subgroup of lanthanides). It is located in group III B, in the 6th period of the periodic system. 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.
Discovery history
Europium was discovered by E. Demarce 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 content of europium in the earth's crust is 1.310 -4%, in sea water 1.110 -6 mg/l. Included in the minerals monazite (cm. MONACITE), loparite (cm. LOPARIT), bastnäsite (cm. BASTNEZIT) and others.
Receipt
Europium metal is obtained by reducing 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 silvery gray metal. Cubic lattice type a-Fe, a= 0.4582 nm. Melting point 826 ° C, boiling point 1559 ° C, density 5.245 kg / dm 3.
In air, europium is covered with a film of oxides and hydrated carbonates. With a slight heating, it oxidizes quickly. When slightly heated, it reacts with halogens, nitrogen and hydrogen. Reacts with water and mineral acids at room temperature.
Oxide Eu 2 O 3 has basic properties, it corresponds to a strong base Eu (OH) 3. When Eu and Eu 2 O 3 react, as well as when trivalent europium oxyhalides interact with lithium hydride LiH, europium (II) oxide EuO is formed. This oxide corresponds to the base Eu(OH) 2 .
Application
It is used as a neutron absorber in nuclear technology, an activator of red glow 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 as an oxide in 1896. Europium is mined from the minerals monazite and bastnäsite. Used in the manufacture of color television screens, ... ... Scientific and technical encyclopedic dictionary

    - (Europium), Eu, a chemical element of group III of the periodic system, atomic number 63, atomic mass 151.96; refers to rare earth elements; metal. Discovered by the French chemist E. Demarce in 1901 ... Modern Encyclopedia

    - (lat. Europium) Eu, a chemical element of group III of the periodic system, atomic number 63, atomic mass 151.96, belongs to the lanthanides. Metal, density 5.245 g/cm³, mp 826.C. Name from Europe (part of the world). Neutron absorber in ... ... Big Encyclopedic Dictionary

    - (Europium), Eu chem. group III element periodic. systems of elements, at. number 63, at. mass 151.96, is a member of the lanthanide family. Natural E. consists of isotopes with mass numbers 151 (47.82%) and 153 (52.18%). The electronic configuration of three ... ... Physical Encyclopedia

    Exist., number of synonyms: 3 lanthanide (15) metal (86) element (159) ASIS synonym dictionary ... Synonym dictionary

    europium- Eu Chemical element; refers to lantonides; in the form of an oxide, it is used in nuclear power engineering as a burnable absorber. [A.S. Goldberg. English Russian Energy Dictionary. 2006] Topics Energy in general Synonyms Eu EN europium … Technical Translator's Handbook

    Europium- (Europium), Eu, a chemical element of group III of the periodic system, atomic number 63, atomic mass 151.96; refers to rare earth elements; metal. Discovered by the French chemist E. Demarce in 1901. ... Illustrated Encyclopedic Dictionary

    63 Samarium ← Europium → Gadolinium ... Wikipedia

    - (lat. Europium), chem. element III gr. period wild. systems, refers to the lanthanides. Metal, thick 5.245 g/cm3, mp 826 0С. Name from Europe (part of the world). Neutron absorber in nuclear reactors, phosphor activator in col. TVs... Natural science. encyclopedic Dictionary

    - (prop.) chem. 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,. "Popular Library of Chemical Elements" contains information about all the elements known to mankind. Today there are 107 of them, and some are obtained artificially. How dissimilar properties...

Europium is a chemical element in the periodic table. It is used in energy, medicine and electronics and is the most expensive representative of the lanthanides. What are the properties and characteristics of europium?

Element 63

The chemical element europium was first discovered by Englishman William Crookes in 1886. But its properties became known far from immediately. Repeatedly, Crookes and other scientists saw only the spectral lines of a substance unknown to them. Its discovery is attributed to the Frenchman Eugene Demarce, who not only discovered the element, but also isolated it from the mineral, described it and gave the name.

Europium is a metal with an atomic number of 63. It does not occur on its own and is present in nature as part of rare earth minerals, such as monazite and xenotime. The amount of the chemical element europium in the earth's crust is 1.2 * 10 -4%. For industrial production, metal is mined from monazite, since its content in this mineral reaches 1%.

The largest deposits of europium are in Kenya. It is also found in the USA, Brazil, Australia, Scandinavian countries, Russia, Kazakhstan, etc.

Main characteristics

The chemical element europium is a silver-white metal. Its atomic mass is 151.964 (1) g/mol. It is soft and easily amenable to mechanical action, but only with an inert atmosphere, as it is a fairly active substance.

The melting point of the metal is 826 degrees Celsius, europium boils at a temperature of 1529 degrees. It can become superconductive (becomes capable of zero electrical resistance) at a pressure of 80 GPa and a temperature of -271.35 Celsius (1.8 K).

There are two natural isotopes of the element europium 153 and europium 151 with different numbers of neutrons in the nucleus. The first is quite stable and is slightly more common in nature. The second isotope is unstable and has alpha decay. The period of the chemical element europium 151 is 5×10 18 years. In addition to these isotopes, there are 35 more artificial ones. The longest has Eu 150 (half-life 36.9 years), and one of the fastest - Eu 152 m3 (half-life 164 nanoseconds).

Chemical properties

The chemical element europium is in the lanthanide group, along with Lanthanum, Cerium, Gadolinium, Promethium and others. He is the lightest and most active of all his "classmates". Europium quickly reacts with air, oxidizing and becoming covered with a film. Because of this, it is usually stored in paraffin or kerosene in special containers and flasks.

Europium is also active in other reactions. In compounds, it is usually trivalent, but sometimes divalent. When heated in an oxygen atmosphere, it forms the compound Eu 2 O 3 in the form of a white-pink powder. With a slight heating, it easily reacts with nitrogen, hydrogen and halogens. Many of its compounds are white with lighter shades of orange and pink.

Europium (III) cations are obtained by decomposition of solutions of salts of sulfate, oxalate, nitrate. In industry, the metal is obtained using carbon or lanthanum by reducing its oxide or by electrolysis of its EuCl 3 alloy.

Of all the lanthanides, only the emission spectrum of europium (III) ions can be perceptible to the human eye. When used to generate laser radiation, the color of its beam is orange.

Application

The use of the chemical element europium found in the field of electronics. In color television, it is used to activate red or blue phosphors. Its combination with silicon EuSi 2 forms thin films and is used for the manufacture of microcircuits.

The element is used for the production of fluorescent lamps and fluorescent glass. In medicine, it has been used to treat certain forms of cancer. Its artificial isotope europium 152 serves as an indicator, and the isotope number 155 is used for medical diagnostics.

It absorbs thermal neutrons more than other lanthanides, which is very useful in nuclear power engineering. For these purposes, its oxide, a compound with boric acid (europium borate) and a binary compound with boron (europium hexaboride) are used. The element is also used in atomic hydrogen energy during the thermochemical decomposition of water.

Harm and impact on humans

Europium is found in small amounts in the human body. It can also be contained in water, getting into it in the areas of mineral deposits in which it is included. Industrial production also supplies water with this element.

The effect of the element on the body and human health has not been studied. Trusting the widespread information, it does not pose a particular danger, since its concentrations are usually too small.

Europium has very little toxicity, and its content in water is usually so insignificant that it cannot significantly affect its quality. In fresh and low-salt waters, its amount reaches 1 μg / l, in sea water this figure is 1.1 * 10 -6 mg / l.


Europeum

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Checked by: Zhumadilov K.Sh.

Astana, 2015

Discovery history

The discovery of europium is associated with the early spectroscopic work of Crookes and Lecoq de Boisbaudran. In 1886, Crookes, studying the phosphorescence spectrum of the mineral samarskite, discovered a band in the wavelength region of 609 A. He observed the same band when analyzing a mixture of ytterbium and samarium earths. Crookes did not give a name to the suspected element and temporarily designated it with the index Y. In 1892, Lecoq de Boisbaudran received from Cleve 3 g of purified samarium earth and produced its fractional crystallization. After spectroscopy of the obtained fractions, he discovered a number of new lines and designated the proposed new element with the indices Z (epsilon) and Z (zetta). Four years later, Demarsay, as a result of long painstaking work on isolating the desired element from samarium earth, clearly saw the spectroscopic band of the unknown earth; he gave her the index "E". It was later proved that Z(epsilon) and Z(zetta) by Lecoq de Boisbaudran, Demarsay's "E" and the anomalous bands of the spectrum observed by Crookes refer to the same element, named by Demarsay in 1901 as europium (Europium) in honor of the European continent.

EUROPIUM(Europium), Eu - chem. group III element periodic. systems of elements, at. number 63, at. mass 151.96, is a member of the lanthanide family. Natural E. consists of isotopes with mass numbers 151 (47.82%) and 153 (52.18%). Electronic configuration of three ext. shells 4s 2 p 6 d 10 f 7 5s 2 p 6 6s 2 . The energies are followed. ionizations are 5.664, 11.25 and 24.7 eV. Crystallohim. the radius of the Eu atom is 0.202 nm (the largest among the lanthanides), the radius of the Eu 3+ ion is 0.097 nm. The electronegativity value is 1.01. In free form - silver-white metal, body-centered cubic crystal lattice with constant lattice a= 0.45720 nm. Density 5.245 kg / dm 3, t pl \u003d 822 ° С, t kip \u003d 1597 ° С. Heat of fusion 9.2 kJ/mol, heat of vaporization 146 kJ/mol, sp. heat capacity 27.6 J/mol.K, sp. resistance 8.13.10 -5 Ohm.cm (at 25 °C). Paramagnetic, magnetic susceptibility 22.10 -8 . In chem. compounds exhibits oxidation states +2 and +3. Natural isotopes E. have high thermal neutron capture cross sections, so E. is used as an eff. neutron absorber. Eu serves as an activator in decomp. phosphors based on compounds Y, Zn, etc. Lasers based on ruby ​​activated by Eu 3+ give radiation in the visible region of the spectrum. Of the radionuclides, most (b - radioactive 152 Eu (T 1/2 \u003d 13.33 g) and 154 Eu (T 1/2 \u003d 8.8 g) used in g-defectoscopy and other purposes are of importance.

For the ROSFOND library, it was required to select neutron data for 12 stable and long-lived isotopes of europium. Data for all these isotopes are contained in the FOND-2.2 library. However, as will be seen below, it would be expedient to replace neutron data for a number of isotopes with more modern and complete estimates made in recent years. Let us consider the results of the re-evaluation of data for europium isotopes carried out in recent years in comparison with the estimates contained in FOND-2.2. In this case, the main attention will be paid to the results of estimating the capture cross section. All experimental data used in comparison with the estimated cross sections were taken from the EXFOR-CINDA database (version 1.81, June 2005). Recommended Muhabhab values ​​are given according to “Thermal Neutron Capture Cross Sections, Resonance Integrals and G-factors”, INDC(NDS)-440, 2003. Radioactive Isotopes. For the 6 long-lived dysprosium isotopes –145Eu, 146Eu, 147Eu, 148Eu, 149Eu, and 150Eu, there are no complete neutron data sets. In the FOND-2.2 library, the neutron data for them were taken from EAF-3. In the version of the EAF-2003 library, the data on radioactive neutron capture remained practically unchanged for the most part, however, the remaining cross sections were revised taking into account calculations using programs that implement new theoretical models. Separately, the long-lived isotopes 152Eu, 154Eu, 155Eu, and 156Eu, for which complete sets of neutron data were available, should be noted. These isotopes are characterized by large radiative capture cross sections and long lifetimes. They are fission products that make an appreciable total contribution to the total absorption cross section of all fission products. stable isotopes. The data for europium stable isotopes in the FOND-2.2 library were taken from the JENDL-3.3 library with minor data corrections (March 1990). The changes concerned the revision of cross sections for threshold reactions. The JEF-3.1 library for Eu-151 uses the evaluation done for JEF-2.2 (~ENDF/B-V). For Eu-153, an estimate made for the JENDL-3.2 Japanese Neutron Data Library. In JENDL-3.3, neutron data has not been revised since JENDL-3.2 (March 1990). ENDF.B-VII (betha 1.2 version, November 2005) adopted an assessment made by the International Fission Products Library project. The authors of the assessment: Muhabhab (S.Mughabghab, BNL) - (resonant region); Oblozhinsky (P. Oblozinsky, BNL), Rohman (D. Rochman, BNL) and Herman (M. Herman, BNL) - (higher energy region. When analyzing neutron data for individual isotopes, we will proceed from the general information presented above. Europium-152 The isotope Eu-152 is formed by burning out the stable isotope Eu-151. It has three isomeric In the ground state, the half-life is T1 \ 2 = 13.516 years, from which the isotope, with ~ 70% probability undergoing β-decay, turns into a stable isotope Gd-150 (α-active), and with ~ 30% probability as a result of positron decay turns into Sm-152. In the first isomeric state, the half-life is 9.31 hours. The decay chain is similar to the ground state, with the only difference that the probabilities of the decay processes are reversed. The probability of an isomeric transition is negligible. In the second isomeric state (T1\2 =96 min.) undergoes an isomeric transition to the ground state with the emission of a γ-quantum. In FOND-2.2 - the estimate made by J.Kopecky, D.Nierop, 1992 (EAF-3). In JEFF-3.1 - the estimate made for JENDL-3.2 .J ENDL-3.3 is an assessment made for JENDL-3.2 with minor changes, 1990. In ENDF/B-VII b1.2 is an assessment by R.Wright and JNDC FPND W.G. (2005) for the International Fission Products Library. In the region of allowed resonances (1.Е-5 eV - 62.07 eV), the ENDF/B estimate was used, above, the JENDL-3.3 estimate. Some characteristics for the resonant energy region are given in Table 2. They were obtained using the INTER program from the ENDF UTILITY CODES software package (release 6.13, July 2002). It can be seen from the information in Table 2 that both the ENDF/B estimate and the JENDL estimate agree with the experimental value of the capture cross section. Note that there is a strong discrepancy between the value of the resonance integral recommended by Muhabhab (BNL-325, 1981) and the values ​​obtained from the estimated cross sections. It is also clear from the tabular data that the estimate accepted by the FUND needs to be revised. Figure 10 compares the estimated cross sections for neutron radiative capture in the resonant energy region. The comparison in Figure 10 shows that the ENDF/B estimate significantly expands the region of allowed resonances. When describing resonances in the region of 2 eV, the ENDF/B estimate is higher than the JENDL estimate, which causes small discrepancies in the value of the resonance integral between these estimates.

Scope of europium

Europium metal, designation according to Russian standards EvM-1 according to that 48-2-217-72, ingots, chemical purity 99.9% or more. They belong to the rare earth elements (the cerium subgroup of the lanthanides). It is located in group 111 in, in the 6th period of the periodic system, Europium is the lightest of the lanthanides. it is unstable among the Saami rare earth elements - in the presence of atmospheric oxygen and moisture, it quickly oxidizes (corrodes). Europium is the most active and one of the most expensive lanthanides. It is used as a financial instrument. The technical application of europium is as follows:

1. Nuclear power: europium is used as a neutron absorber in nuclear reactors, the most active in terms of neutron capture is europium-151. this provides highly effective protection against hard radiation in a wide range of wavelengths.

2. Atomic-hydrogen energy: Europium oxide is used in the thermochemical decomposition of water in nuclear-hydrogen energy (Europium-strontium-iodide cycle).

3. Laser materials: Europium ions are used to generate laser radiation in the visible region of the spectrum (orange rays), so europium oxide is used to create solid-state, liquid lasers.。

4. Electronics: Europium is a dopant in samarium monosulfide (thermoelectric generators), and also as an alloying component for the synthesis of diamond-like (superhard) carbon nitride. Europium silicide in the form of thin films is used in integrated microelectronics.

5. Europium monoxide is used in the form of thin films as magnetic semiconductor materials for rapidly developing functional electronics, and in particular MIS - electronics

6. Phosphors: Europium tungstate is a phosphor used in microelectronics and television. Europium-doped strontium borate is used as a phosphor in black light lamps.

7. Europium in medicine: Europium and cations are successfully used in medicine as fluorescent probes. Radioactive isotopes of Europium are used in the treatment of certain forms of cancer.

8. Other uses of europium: photosensitive compounds of europium with bromine, chlorine and iodine are being intensively studied. Europium-154 has a high heat release rate during radioactive decay and has been proposed as a fuel in radioisotope energy sources. Europium, separated from other lanthanides, is alloyed with some special alloys, in particular alloys based on zirconium.


Similar information.


The last rare-earth element of the cerium subgroup - europium - as well as its neighbors in the periodic table, is one of the strongest absorbers of thermal neutrons. This is the basis for its application in nuclear technology and radiation protection technology.
As a material for anti-neutron shielding, element No. 63 is interesting in that its natural isotopes 151 Eu and 153 Eu, by absorbing neutrons, are converted into isotopes with almost the same large thermal neutron capture cross section.

Radioactive europium, produced in nuclear reactors, has been used in the treatment of certain forms of cancer.
Europium has become important as a phosphor activator. In particular, yttrium oxide, oxysulfide and yttrium 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 some special alloys, in particular alloys based on zirconium, have been alloyed with europium separated from other lanthanides.
Element No. 63 is not like other rare earth elements in everything. - 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 the lanthanides. With these "anomalies" in the properties of element No. 63, some researchers also associate 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, but gradually turns white during storage. Apparently, further oxidation by atmospheric oxygen to Eu 2 0 3 takes place here.
As we already know, in compounds europium is divalent and trivalent. Most of its compounds are white, usually with a creamy, pinkish or light orange tint. Europium compounds with chlorine and bromine are photosensitive.
As is known, the 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 gives radiation in the part of the spectrum perceived by the human eye. The europium laser beam is orange.

Origin of the name europium

Where does the name of element number 63 come from, it is not difficult to understand. As for the history of the discovery, it was difficult and long to open it.
In 1886, the French chemist Demarsay isolated a new element from Samarpe soil, 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. A similar report was made six years later by Lecoq de Boisbaudran. But all the data about the new element was 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.
Europium metal was first obtained only in 1937..

Description

The electronic structure of the europium atom Eu I contains 63 electrons, which filled 13 shells. The base term is the octet 8 S 7/2 of the configuration 4f 7 6s 2 . When an s-electron is excited, various terms of the 4f 7 6snl, 4f 7 5dnl, and 4f 7 nl 2 configurations arise with a high multiplicity (6,8,10) in the LS bond, which form the spectrum. The optical spectrum of the Eu I atom was first studied by Russell H. and King A. (1934). Above the first ionization limit (45734.9 cm -1) there are configuration levels 4f 7 5dnp, above the second (47404.1 cm -1) - unclassified levels. To date, the degree of knowledge of Eu I is low, there are many unclassified levels and transitions.

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