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युरोपियम [[रेर अर्थ तत्त्व]]य् दक्ले रियाक्टिभ तत्त्व ख। थ्व तत्त्व वातावरणय् छकलं अक्सिडाइज जुइ व थुकिया लनापया रियाक्सन क्याल्सियमया थें न्यागु जुइ। थ्व धातुया ठोस रुपयात मिनरल चिकंनं भुनातःसां थुकिलि शाइन दैमखु। युरोपियम वायुइ १५०-१८०डि॰से॰य् च्याइ। थ्व तत्त्व लिड ति हे कडा जु व सिक्क [[डक्टाइल]] नं जु। युरोपियम छगू धातु ख व थ्व ८०जिपास्कलय् १.८ केल्भिनय् सुपरकन्डक्टर जुइ। <ref>{{cite journal| author = M. Debessai et al. | title = Pressure-Induced Superconducting State of Europium Metal at Low Temperatures| journal = Phys. Rev. lett.| doi = 10.1103/PhysRevLett.102.197002| volume =102| page =197002| year = 2009}}</ref>
 
== कम्पाउन्द ==
== Compounds ==
युरोपियमया कम्पाउन्दत थ्व कथं दु:
Europium compounds include:
 
* [[Fluorideफ्लोराइद]]s: [[europium(II) fluoride|EuF<sub>2</sub>]], [[europium(III) fluoride|EuF<sub>3</sub>]]
* [[Chlorideक्लोराइद]]s: [[europium(II) chloride|EuCl<sub>2</sub>]], [[europium(III) chloride|EuCl<sub>3</sub>]]
* [[Bromideब्रोमाइद]]s: [[europium(II) bromide|EuBr<sub>2</sub>]], [[europium(III) bromide|EuBr<sub>3</sub>]]
* [[Iodideआयोदाइद]]s: [[europium(II) iodide|EuI<sub>2</sub>]], [[europium(III) iodide|EuI<sub>3</sub>]]
* [[Oxideअक्साइद]]s: [[europium(II) oxide|EuO]], [[europium(III) oxide|Eu<sub>2</sub>O<sub>3</sub>]], [[europium(IV) oxide|Eu<sub>3</sub>O<sub>4</sub>]]
* [[Sulfideसल्फाइद]]s: [[europium(II) sulfide|EuS]]
* [[Selenideसेलेनाइद]]s: [[europium(II) selenide|EuSe]]
* [[telluride (chemistry)|Telluridesतेलुराइद]]: [[europium(II) telluride|EuTe]]
* [[Nitrideनाइत्राइद]]s: [[europium(III) nitride|EuN]]
Europium(II) compounds tend to predominate, in contrast to most [[Lanthanoid|lanthanides]]: (which generally form compounds with an oxidation state of +3). Europium(II) chemistry is very similar to [[barium]](II) chemistry, as they have similar [[ionic radius|ionic radii]]. Divalent europium is a mild reducing agent, such that under atmospheric conditions, it is the trivalent form that predominates. Under anaerobic, and particularly under geothermal conditions, the divalent form is sufficiently stable such that it tends to be incorporated into minerals of calcium and the other alkaline earths. This is the cause of the "negative europium anomaly", that depletes europium from being incorporated into the most usual light lanthanide minerals such as monazite, relative to the chondritic abundance. Bastnäsite tends to show less of a negative europium anomaly than monazite does, and hence is the major source of europium today.
The accessible divalency of europium has always made it one of the easiest lanthanides to extract and purify, even when present, as it usually is, in low concentration.
''See also [[:Category:Europium compounds|europium compounds]].''
 
== Isotopesलिधंसा ==
{{main|Isotopes of europium}}
Naturally occurring europium is composed of 2 [[isotope]]s, <sup>151</sup>Eu and <sup>153</sup>Eu, with <sup>153</sup>Eu being the most abundant (52.2% [[natural abundance]]). While <sup>153</sup>Eu is stable, <sup>151</sup>Eu was recently found to be unstable to [[alpha decay]] with [[half-life]] of <math>5_{-3}^{+11}\times 10^{18}</math> yr<ref>Search for α decay of natural Europium, P. Belli, R. Bernabei, F. Cappell, R. Cerulli, C.J. Dai, F.A. Danevich, A. d'Angelo, A. Incicchitti, V.V. Kobychev, S.S. Nagorny, S. Nisi, F. Nozzoli, D. Prosperi, V.I. Tretyak, and S.S. Yurchenko, Nucl. Phys. A '''789''', 15 (2007) {{doi|10.1016/j.nuclphysa.2007.03.001}}</ref> (in reasonable agreement with theoretical predictions), giving about 1 alpha decay per two minutes in every kilogram of natural europium. Besides natural radioisotope <sup>151</sup>Eu, 35 artificial radioisotopes have been characterized, with the most stable being <sup>150</sup>Eu with a [[half-life]] of 36.9 years, <sup>152</sup>Eu with a half-life of 13.516 years, and <sup>154</sup>Eu with a half-life of 8.593 years. All of the remaining [[radioactive]] isotopes have half-lives that are less than 4.7612 years, and the majority of these have half-lives that are less than 12.2 seconds. This element also has 8 [[meta state]]s, with the most stable being <sup>150m</sup>Eu (''T''<sub>½</sub>=12.8 hours), <sup>152m1</sup>Eu (''T''<sub>½</sub>=9.3116 hours) and <sup>152m2</sup>Eu (''T''<sub>½</sub>=96 minutes).
 
The primary [[decay mode]] before the most abundant stable isotope, <sup>153</sup>Eu, is [[electron capture]], and the primary mode after is [[beta minus decay]]. The primary [[decay product]]s before <sup>153</sup>Eu are isotopes of [[samarium]] (Sm) and the primary products after are isotopes of [[gadolinium]] (Gd).
 
== Europium as a nuclear fission product ==
 
{| class="wikitable" align="right"
|+ Thermal neutron capture cross sections
!Isotope
|<sup>151</sup>Eu||<sup>152</sup>Eu||<sup>153</sup>Eu||<sup>154</sup>Eu||<sup>155</sup>Eu
|-
!Yield
|~10||low||1580||>2.5||330
|-
!Barns
|5900||12800||312||1340||3950
|}
{{Medium-lived fission products}}
Europium is produced by nuclear fission, but the [[fission product yield]]s of europium isotopes are low near the top of the mass range for [[fission products]].
 
Like other [[Lanthanoid|lanthanides]], many isotopes, especially isotopes with odd mass numbers and neutron-poor isotopes like <sup>152</sup>Eu, have high [[Neutron cross-section|cross sections]] for [[neutron capture]], often high enough to be [[neutron poison]]s.
 
<sup>151</sup>Eu is the [[beta decay]] product of [[Sm-151]], but since this has a long decay half-life and short mean time to neutron absorption, most <sup>151</sup>Sm instead winds up as <sup>152</sup>Sm.
 
<sup>152</sup>Eu (half-life 13.516 years) and <sup>154</sup>Eu (halflife 8.593 years) cannot be beta decay products because <sup>152</sup>Sm and <sup>154</sup>Sm are nonradioactive, but <sup>154</sup>Eu is the only long-lived "shielded" [[nuclide]], other than [[Cs-134|<sup>134</sup>Cs]], to have a fission yield of more than 2.5 [[parts per million]] fissions.<ref>ORNL Table of the Nuclides</ref> A larger amount of <sup>154</sup>Eu will be produced by [[neutron activation]] of a significant portion of the nonradioactive<sup>153</sup>Eu; however, much of this will be further converted to <sup>155</sup>Eu.
 
[[Eu-155|<sup>155</sup>Eu]] (halflife 4.7612 years) has a fission yield of 330 ppm for [[Uranium-235|U-235]] and [[thermal neutron]]s. Most will be transmuted to nonradioactive and nonabsorptive [[Gadolinium]]-156 by the end of fuel [[burnup]].
 
Overall, europium is overshadowed by [[Cs-137]] and [[Sr-90]] as a radiation hazard, and by [[samarium]] and others as a neutron poison.
 
== Precautions ==
The toxicity of europium compounds has not been fully investigated, but there are no clear indications that europium is highly toxic compared to other heavy metals. The metal dust presents a fire and explosion hazard. Europium has no known biological role.
 
== Isolation of Europium ==
 
Europium metal is available commercially, so it is not normally necessary to make it in the laboratory — which is just as well, as it is difficult to isolate as the pure metal. This is largely because of the way it is found in nature, wherein the lanthanoids are found in a number of minerals. The most important are [[xenotime]], [[monazite]], and [[bastnäsite]]. The first two are orthophosphate minerals LnPO<sub>4</sub> (Ln denotes a mixture of all the lanthanoids except [[promethium]] which is vanishingly rare due to being radioactive) and the third is a fluoride carbonate LnCO<sub>3</sub>F. Lanthanoids with even atomic numbers are more common. The most common lanthanoids in these minerals are, in order, [[cerium]], [[lanthanum]], [[neodymium]], and [[praseodymium]]. Monazite also contains [[thorium]] and [[yttrium]], which makes handling difficult since thorium and its decomposition products are radioactive.
 
For many purposes it is not particularly necessary to separate the metals, but if separation into individual metals is required, the process is complex. Initially, the metals are extracted as salts from the ores by extraction with [[sulfuric acid]] (H<sub>2</sub>SO<sub>4</sub>), [[hydrochloric acid]] (HCl), and [[sodium hydroxide]] (NaOH). Modern purification techniques for these lanthanoid salt mixtures are ingenious and involve selective [[complexation]] techniques, [[solvent extraction]]s, and [[ion exchange chromatography]].
 
Pure europium is available through the electrolysis of a mixture of molten EuCl<sub>3</sub> and NaCl (or CaCl<sub>2</sub>) in a graphite cell which acts as cathode, using graphite as anode. The other product is [[chlorine]] gas.
 
== References ==
{{reflist}}
 
 
== पिनेया स्वापू ==
== External links ==
{{Commons|Europium}}
{{wiktionary|europium}}
Line ७४ ⟶ २८:
* [http://education.jlab.org/itselemental/ele063.html It's Elemental – Europium]
{{clear}}
 
{{Compact periodic table}}
{{तत्त्व}}
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