Jump to navigation Jump to search

Template:Elementbox header Template:Elementbox series Template:Elementbox periodblock Template:Elementbox appearance Template:Elementbox atomicmass gpm Template:Elementbox econfig Template:Elementbox epershell Template:Elementbox section physicalprop Template:Elementbox phase Template:Elementbox density gpcm3nrt Template:Elementbox meltingpoint Template:Elementbox section atomicprop Template:Elementbox oxistates Template:Elementbox electroneg pauling Template:Elementbox ionizationenergies1 Template:Elementbox section miscellaneous Template:Elementbox magnetic Template:Elementbox cas number |- ! colspan="2" style="background:#ff99cc; color:black" | Selected isotopes |- | colspan="2" |

iso NA half-life DM DE (MeV) DP

Template:Elementbox isotopes decay3 Template:Elementbox isotopes decay2 Template:Elementbox isotopes decay3 Template:Elementbox isotopes decay3 Template:Elementbox isotopes end Template:Elementbox footer

Einsteinium (Template:PronEng) is a synthetic element. On the periodic table, it is represented by the symbol Es and atomic number 99. It is the seventh transuranic element, and seventh in the series of Actinides. It was named in honor of Albert Einstein.[1]


Its position on the periodic table indicates that its chemical and physical properties are similar to other metals. Though only small amounts have ever been made, it has been determined to be silver-colored.[1] According to tracer studies conducted at Los Alamos National Laboratory using the isotope 253Es, this element has chemical properties typical of a heavy trivalent, actinide element.[2]

Like many of the synthetic elements, many of einsteinium's isotopes are radioactive.


Einsteinium does not occur naturally in any measurable quantities. The modern process of creating the element starts with the irradiation of Plutonium-239 in a nuclear reactor for several years. The resulting Plutonium-242 isotope (in the form of the compound Plutonium(IV) oxide) is mixed with aluminum and formed into pellets. The pellets are then further irradiated for approximately one year in a nuclear reactor. Another four months of irradition is required in a different reactor. The result is a mixture of californium and einsteinium, which can then be separated.[2]


Aside from being the byproduct of creating other elements, or a step in the production of other elements, einsteinium has no known uses.[3]


Einsteinium was first identified in December 1952 by Albert Ghiorso at the University of California, Berkeley.[2] He was examining debris from the first hydrogen bomb test of November 1952 (see Operation Ivy).[1] He discovered the isotope 253Es (half-life 20.5 days) that was made by the nuclear fusion of 15 neutrons with 238U (which then went through seven beta decays). These findings were kept secret until 1955 due to Cold War tensions.

In 1961, enough einsteinium was synthesized to prepare a microscopic amount of 253Es. This sample weighed about 0.01 mg and was measured using a special balance. The material produced was used to produce mendelevium. Further einsteinium has been produced at the Oak Ridge National Laboratory's High Flux Isotope Reactor in Tennessee by bombarding 239Pu with neutrons. Around 3 milligrams were created over a four year program of irradiation and then chemical separation from a starting 1 kg of plutonium isotope.


Nineteen radioisotopes of einsteinium have been characterized,[4] with the most stable being 252Es with a half-life of 471.7 days, 254Es with a half-life of 275.7 days, 255Es with a half-life of 39.8 days, and 253Es with a half-life of 20.47 days. All of the remaining radioactive isotopes have half-lives that are less than 40 hours, and the majority of these have half-lives that are less than 30 minutes. This element also has three meta states, with the most stable being 254mEs (t½ 39.3 hours). The isotopes of einsteinium range in atomic mass from 240.069 u (240Es) to 258.100 u (258Es). The most original isotope is the 252Es.

Known compounds

The following is a list of all known compounds of einsteinium:[5]

  • EsBr2 einsteinium(II) bromide
  • EsBr3 einsteinium(III) bromide
  • EsCl2 einsteinium(II) chloride
  • EsCl3 einsteinium(III) chloride
  • EsF3 einsteinium(III) fluoride
  • EsI2 einsteinium(II) iodide
  • EsI3 einsteinium(III) iodide
  • Es2O3 einsteinium(III) oxide


  • Guide to the Elements - Revised Edition, Albert Stwertka, (Oxford University Press; 1998) ISBN 0-19-508083-1

External links

ar:أينشتينيوم az:Eynşteynium bn:আইনস্টাইনিয়াম be:Эйнштэйній bs:Ajnštajnijum ca:Einsteini cs:Einsteinium co:Einsteiniu da:Einsteinium de:Einsteinium et:Einsteinium el:Αϊνσταΐνιο eo:Ejnŝtejnio eu:Einstenio fa:اینشتینیوم fur:Einsteini gl:Einstenio (elemento) ko:아인슈타이늄 hy:Էյնշտեյնիում hr:Einsteinij io:Einsteinio id:Einsteinium it:Einsteinio he:איינשטייניום ka:აინშტაინიუმი ht:Achtaynyòm la:Einsteinium lv:Einšteinijs lb:Einsteinium lt:Einšteinis jbo:jinmrtainctaini hu:Einsteinium nl:Einsteinium no:Einsteinium nn:Einsteinium scn:Einsteiniu simple:Einsteinium sk:Einsteinium sl:Ajnštajnij sr:Ајнштајнијум sh:Ajnštajnijum fi:Einsteinium sv:Einsteinium th:ไอน์สไตเนียม uk:Ейнштейній Template:WikiDoc Sources