Einsteinium was discovered as a component of the debris of the first hydrogen bomb explosion in 1952, and named after Albert Einstein.
Its most common isotope einsteinium-253 (half-life 20.47 days) is produced artificially from decay of californium-253 in a few dedicated high-power nuclear reactors with a total yield on the order of one milligram per year.
Einsteinium is a synthetic element with the symbol Es and atomic number 99. As a member of the actinide series, it is the seventh transuranic element.
Names and Identifiers
|EC Number :||n/a|
|Color:||unknown (presumably metallic/ silvery white/ gray)|
|Other Names:||Einstenio, Einstânio|
Physical & Chemical Properties
|Boiling Point:||1269 K (996 °C, 1825 °F)|
|Melting Point:||1133 K (860 °C, 1580 °F)|
Eighteen nuclides and three nuclear isomers are known for einsteinium, with atomic weights ranging from 240 to 257.
All are radioactive and the most stable nuclide, 252Es, has a half-life of 471.7 days.
The next most stable isotopes are 254Es (half-life 275.7 days), 255Es (39.8 days), and 253Es (20.47 days).
|Isotope||Mass/Da||Half-life||Mode of decay||Nuclear spin||Nuclear magnetic moment|
|249Es||249.07640||1.70 h||EC to 249Cf; α to 245Bk||7/2|
|250Es||250.0787||8.6 h||EC to 250Cf; α to 246Bk||6|
|251Es||251.07998||1.38 d||EC to 251Cf; α to 247Bk||3/2|
|252Es||252.082944 (23)||1.29 y||EC to 252Cf; α to 248Bk; β– to 252Fm||5|
|253Es||253.08482||20.47 d||α to 249Bk; SF||7/2||4.10|
|254Es||254.08802||276 d||EC to 254Cf; α to 250Bk; β– to 254Fm; SF||7|
|255Es||255.09027||40 d||α to 251Bk; β– to 255Fm; SF||7/2|