99
252.00
Es
Einsteinium
Identification
CAS Number: 7429-92-7
Discovery Year: 1952
Discoverer: Argonne, Los Alamos, U of Calif
Discovery Location: United States
Properties
Atomic Dimensions
Van der Waals Radius: 245.00000000000003 pm
Thermodynamics
Boiling Point: 1130 K →
Heat of Formation: 133 kJ/mol
Electronic Structure
Abundance & Geochemistry
Goldschmidt Class: synthetic
About
Appearance is unknown, however it is most probably metallic and silver or gray in color. Radioactive metallic transuranic element belonging to the actinoids. Es-254 has the longest half-life of the eleven known isotopes at 270 days. First identified by Albert Ghiorso and associates in the debris of the 1952 hydrogen bomb explosion. In 1961 the first microgram quantities of Es-232 were separated. While einsteinium never exists naturally, if a sufficient amount was assembled, it would pose a radiation hazard.
Isotopes
Es-252 252 ☢ 472 d
Es-254 254 ☢ 276 d
