Periodic Table of the elements main page

Periodic Table

science park

Table of Elements

Chemical information

Science dictionary

scientific data

Site map

Gifts and souvenirs

printable version

go to periodic table










Education Billboard - meet and serve your education needs

Element Fact
The liquid helium-4 possesses the most unusual physical properties that defy common sense. Below 2.2 K it becomes a superfluid that can flow, against gravity, up the wall of a container.

Einsteinium, Es

einsteinium sample

Atomic number: 99
Atomic mass: [252] (no stable nuclide)
Natural abundance: -
Isotopes: -

History and Production

Named after Albert Einstein (1879-1955). It was discovered by G.R. Choppin, S.G. Thompson, A. Ghiorso and B.G. Harvey in 1952, in the debris of the first large thermonumclear explosion in the Pacific. The isotope produced was 253Es with a half-life of about 20 days. It can also be prepared in nuclear reactors by irridiating 239Pu with neutron over several years. Of nineteen isotopes being found, 254Es has the longest half-life of 276 days.

Physical Data

It is a silvery, highly radioactive metal. It is biologically harmful due to its intense radiological behavior.

Interatomic distance: -
Melting point: 860C
Boiling point: n/a
Thermal conductivity/Wm-1K-1: 10 est. (27C)
Density/kgm-3: n/a

Standard Thermodynamic Data (atomic gas)

Enthalpy of formation: -
Gibbs free energy of formation: -
Entropy: -
Heat capacity: -

Electronic data

Electronic configuration: Electronic configuration: [Rn] 5f11 7s2
Term symbol: 5I15/2
Electron affinity: -   Electronegativity (Pauline): -
Ionization energy (first, second, third): 619.436, -, - kJ/mol

Chemical properties

| Copyright | Privacy | Disclaimer | Contact |

2004-2010, all rights reserved.