Discovery date : 1952
Discovered by: Albert Ghiorso and colleagues
Origin of the name: Einsteinium is named after the renowned physicist Albert Einstein.
Allotropes :
~>EISTEINIUM 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.
| FACT BOX | |||
| Group | Actinides | Melting point | 860°C, 1580°F, 1133 K |
| Period | 7 | Boiling point | Unknown |
| Block | f | Density (g cm−3) | Unknown |
| Atomic number | 99 | Relative atomic mass | [252] |
| State at 20°C | Solid | Key isotopes | 252Es |
| Electron configuration | [Rn] 5f117s2 | CAS number | 7429-92-7 |
| ChemSpider ID | 22356 | ChemSpider is a free chemical structure database | |
Einsteinium was discovered in the debris of the first thermonuclear explosion which took place on a Pacific atoll, on 1 November 1952. Fall-out material, gathered from a neighbouring atoll, was sent to Berkeley, California, for analysis. There it was examined by Gregory Choppin, Stanley Thompson, Albert Ghiorso, and Bernard Harvey. Within a month they had discovered and identified 200 atoms of a new element, einsteinium, but it was not revealed until 1955.
The einsteinium had formed when some uranium atoms had captured several neutrons and gone through a series of capture and decay steps resulting in einsteinium-253, which has a half-life of 20.5 days.
By 1961, enough einsteinium had been collected to be visible to the naked eye, and weighed, although it amounted to mere 10 millionths of a gram.