Einsteinium is a seventh transuranic element first discovered in 1952 at the debris of the first hydrogen bomb explosion. It is a radioactive element and has not much uses outside basic scientific research.
History and Discovery
Einsteinium was first discovered and identified by Albert Ghiorso and his co-workers in December 1952. Ghiorso and his co-workers at University of California, Berkeley, worked in collaboration with Los Alamos and Argonne National Laboratories and found element 99 in the debris of Ivy Mike nuclear test; the first successful test of a hydrogen bomb. At that time multiple neutron absorption was considered to be a rare process but analysing the debris resulted in the identification of isotopes of transuranic elements (plutonium) which need absorption of six neutrons by a uranium-238 nucleus for its formation indicating still more neutrons can be captured by uranium nuclei . From the debris of hydrogen bomb less than 200 atoms of einsteinium were recovered. The finding of element 99 was kept classified because of the on-going cold war and was not published until 1955. The element was named after the scientist Einstein and was given the symbol E which was later changed to Es by IUPAC.
|Periodic Table Classification||Group n/a
|State at 20C||Solid|
|Color||Silvery; glows blue in the dark|
|Electron Configuration||[Rn] 5f11 7s2|
|Electron Shell||2, 8, 18, 32, 29, 8, 2|
|Density||0.00 g.cm-3 at 20°C|
|Atomic Mass||252.00 g.mol -1|
|Electronegativity according to Pauling||1.3|
Einsteinium was found naturally, like other transuranic element, at the natural nuclear fission reactor at Oklo. Natural transformation of existing actinides in earth’s crust forming einsteinium is extremely unlikely event as it requires multiple neutron capture. Hence all the existing einsteinium on earth is man-made and is produced in nuclear weapon tests, high power nuclear reactors or in laboratories and exists only for few years because of its short half-life. It is produced in minute quantity by bombardment of neutrons on lighter actinides in high flux nuclear reactors . Because of its very short half-life relative to the life of earth any einsteinium formed at the time of formation of earth would have decayed by now.
Einsteinium is a soft metal with a silvery appearance. It is highly radioactive and its radioactivity produces a visible glow because of which it appears blue in the dark. Its isotope einsteinium-253 releases heat of about 1000 watts per gram. It has a crystalline metal lattice which gets damage with radioactivity and its heat release. It has relatively low density of 8.84 g/cm3. The bulk modulus of einsteinium is one of the lowest among the non-alkali metals . Einsteinium has a melting point of 860 degree centigrade. Einsteinium has an atomic number 99 and is represented by symbol Es.
Einsteinium is a reactive element like all other actinides. It has the most stable oxidation state of +3 in both solids and aqueous solutions. Einsteinium also exists in divalent state unlike many other actinides in solid phase. Its chemical properties resemble to the chemical properties of its immediate neighbouring elements.
Significance and Uses
- Einsteinium has currently no known uses apart from its use in basic scientific research aiming at the production of trans-actinides and higher transuranic elements. It is produced in minute quantity as per requirement. Because of its large mass it is favoured for production of ultra-heavy elements .
Most of the data of toxicity of einsteinium is available from the research on animals. Einsteinium is radioactive element and can be absorbed if ingested eventually depositing in bones, lungs, liver and testicles where it decays into other and sometimes more harmful radioactive elements.
Isotopes of Einsteinium
Einsteinium has nineteen isotopes and three nuclear isomers that have been characterized. The atomic weight of these nuclides ranges from 240 to 258. The most stable isotope of einsteinium is einstenium-252 having half-life 471.1 days. Einstenium-254, the next stable isotope, has a half-life of 275.5 days. All the remaining isotopes have half-life ranging from few days (less than 40 days) to few minutes.
. Ghiorso, Albert (2003). “Einsteinium and Fermium”. Chemical and Engineering News. 81 (36): 174–175.
. Ghiorso, Albert; Rossi, G. Bernard; Harvey, Bernard G. & Thompson, Stanley G. (1954). “Reactions of U-238 with Cyclotron-Produced Nitrogen Ions”. Physical Review. 93 (1): 257.
. Choppin, G. R.; Thompson, S. G.; Ghiorso, A.; Harvey, B. G. (1954). “Nuclear Properties of Some Isotopes of Californium, Elements 99 and 100”. Physical Review. 94 (4): 1080–1081.
. Harvey, Bernard; Thompson, Stanley; Ghiorso, Albert; Choppin, Gregory (1954). “Further Production of Transcurium Nuclides by Neutron Irradiation”. Physical Review. 93 (5): 1129.