Description
Caesium-137 (137
55Cs
), cesium-137 (US), or radiocaesium , is a radioactive isotope of
caesium that is formed as one of the more common fission products by the
nuclear fission of uranium-235 and other fissionable isotopes in nuclear
reactors and nuclear weapons. Trace quantities also originate from spontaneous
fission of uranium-238. It is among the most problematic of the short-to-
medium-lifetime fission products. Caesium-137 has a relatively low boiling
point of 671 °C (1,240 °F) and easily becomes volatile when released suddenly
at high temperature, as in the case of the Chernobyl nuclear accident and with
atomic explosions, and can travel very long distances in the air. After being
deposited onto the soil as radioactive fallout, it moves and spreads easily in
the environment because of the high water solubility of caesium's most common
chemical compounds, which are salts. Caesium-137 was discovered by Glenn T.
Seaborg and Margaret Melhase.
