Plutonium

Plutonium (Pu) is a radioactive, heavy metal with the atomic number 94.

It was discovered in 1940 by scientists studying how to split atoms to make atomic bombs. Plutonium is created in a reactor when uranium atoms absorb neutrons. Nearly all plutonium is man-made.

Plutonium is used as fuel in certain types of nuclear reactors and as an ingredient in nuclear weapons. Over one-third of the energy produced in most nuclear power plants comes from plutonium.

Plutonium is chemically toxic to the human body, like some other heavy metals like lead and mercury. It is also radioactive and causes harmful radiation effects. Animal studies indicate that a few milligrams of plutonium per kilogram of tissue is a lethal dose.

Plutonium is a silvery-gray metal that tarnishes when exposed to air, and forms a dull coating when oxidized. It normally exhibits six allotropes and four oxidation states