Einsteinium (Es)

Isotopes of Einsteinium 

Einsteinium is a radioactive rare earth metal, discovered in 1952 by workers at Argonne and Los Alamos National Laboratories, along with the University of California - Berkeley, USA. It was identified by Albert Ghiorso and others in radioactive debris from the first large thermonuclear bomb explosion, which took place in the Pacific in November 1952. In 1961, a sufficient amount of einsteinium was produced to permit separation of a macroscopic amount of Einsteinium-253. It is named for Albert Einstein.

Einsteinium is a soft, silvery white, paramagnetic metal, believed to have a face-centered cubic structure. Einsteinium-253's conversion to berkelium and then californium at a rate of about 3% per day — along with its scarcity — makes it difficult to study einsteinium's properties; however, it shares many similarities with holmium in its physical and chemical properties. 

There is almost no use for any isotope of einsteinium outside of basic scientific research aiming at production of higher transuranic elements and transactinides; however, Einsteinium-254 was used as the calibration marker in the chemical analysis spectrometer of the Surveyor 5 lunar probe. All isotopes of einsteinium are extremely radioactive and are considered highly dangerous to health upon ingestion. 

Properties of Einsteinium