What is "einsteinium"

Es \Es\ n. the chemical symbol for einsteinium, a transuranic element with atomic number 99. The atomic weight of the longest-lived isotope, with a half-life of 276 days, is 254. The first isotope discovered, having atomic weight 253 and a half-life of 20 days, was recognized in 1952 in the debris from a hydrogen bomb test. As much as 3 micrograms of einsteinium were produced by a complex process involving long irradiation of plutonium isotopes in nuclear reactors. Its chemical properties are those of a trivalent actinide element.
--HCP61

Syn: einsteinium, atomic number 99.

radioactive element, discovered in the debris of a 1952 U.S. nuclear test in the Pacific, named 1955 for physicist Albert Einstein (1879-1955).

n. A transuranic chemical element (''symbol'' Es) with atomic number 99.

n. a radioactive transuranic element produced by bombarding plutonium with neutrons [syn: Es, E, atomic number 99]

Einsteinium is a synthetic element with symbol Es and atomic number 99. It is the seventh transuranic element, and an actinide.

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. The reactor synthesis is followed by a complex process of separating einsteinium-253 from other actinides and products of their decay. Other isotopes are synthesized in various laboratories, but at much smaller amounts, by bombarding heavy actinide elements with light ions. Owing to the small amounts of produced einsteinium and the short half-life of its most easily produced isotope, there are currently almost no practical applications for it outside of basic scientific research. In particular, einsteinium was used to synthesize, for the first time, 17 atoms of the new element mendelevium in 1955.

Einsteinium is a soft, silvery, paramagnetic metal. Its chemistry is typical of the late actinides, with a preponderance of the +3 oxidation state; the +2 oxidation state is also accessible, especially in solids. The high radioactivity of einsteinium-253 produces a visible glow and rapidly damages its crystalline metal lattice, with released heat of about 1000 watts per gram. Difficulty in studying its properties is due to einsteinium-253's conversion to berkelium and then californium at a rate of about 3% per day. The isotope of einsteinium with the longest half life, einsteinium-252 (half life 471.7 days) would be more suitable for investigation of physical properties, but it has proven far more difficult to produce and is available only in minute quantities, and not in bulk. Einsteinium is the element with the highest atomic number which has been observed in macroscopic quantities in its pure form, and this was the common short-lived isotope einsteinium-253.

Like all synthetic transuranic elements, isotopes of einsteinium are very radioactive and are considered highly dangerous to health on ingestion.