Einsteinium



99 fermium
Ho
↑
Es
↓
(Uqe)
General
Number einsteinium, Es, 99
actinides
Block f
Appearance unknown, probably silvery
white or metallic gray
Standard atomic weight (252)  g·mol−1
Rn] 5f11 7s2
shell 2, 8, 18, 32, 29, 8, 2
Physical properties
Phase solid
r.t.) 8.84  g·cm−3
F)
Atomic properties
Oxidation states 2, 3, 4
Electronegativity 1.3 (Pauling scale)
Ionization energies 1st: 619 kJ/mol
Miscellaneous
Magnetic ordering no data
CAS registry number 7429-92-7
Selected isotopes
Main article: Isotopes of einsteinium
iso NA half-life DM DE (MeV) DP
252Es syn 471.7 d α 6.760 248Bk
ε 1.260 252Cf
β- 0.480 252Fm
253Es syn 20.47 d SF - -
α 6.739 249Bk
254Es syn 275.7 d ε 0.654 254Cf
β- 1.090 254Fm
α 6.628 250Bk
255Es syn 39.8 d β- 0.288 255Fm
α 6.436 251Bk
SF - -
References

Einsteinium (transuranic element, and seventh in the series of Actinides. It was named in honor of Albert Einstein.[1]

Properties

Its position on the periodic table indicates that its chemical and physical properties are similar to other trivalent, actinide element.[2]

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

Production

Einsteinium does not occur naturally in any measurable quantities. The modern process of creating the element starts with the irradiation of californium and einsteinium, which can then be separated.[2]

Uses

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

History

Einsteinium was 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 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.

Isotopes

Nineteen 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

References

  1. ^ a b c Einsteinium - National Research Council Canada. Retrieved 2 December 2007.
  2. ^ a b c Einsteinium - Los Alamos National Laboratory. Retrieved 2 December 2007.
  3. ^ It's Elemental - The Element Einsteinium. Retrieved 2 December 2007.
  4. ^ Table of Isotopes decay data - LBNL Isotopes Project - LUNDS Universitet. Retrieved 25 November 2007.
  5. ^ Chemistry : Periodic Table : einsteinium : compounds information - WebElements. Retrieved 2 December 2007.
  • Guide to the Elements - Revised Edition, Albert Stwertka, (Oxford University Press; 1998) ISBN 0-19-508083-1
 
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