[{"from": "human", "value": "What can you tell me about this molecule? [239Pu]"}, {"from": "gpt", "value": "The molecule is an element with the symbol Pu and atomic number 94. It is a rare transuranic radioactive element that normally exhibits six allotropes and four oxidation states. It is also a radioactive poison that accumulates in bone marrow. Plutonium-239 is the most important isotope of plutonium, with a half-life of 24,100 years. It is fissile and can therefore sustain a nuclear chain reaction, leading to applications in nuclear weapons and nuclear reactors. Pu-239 is synthesized by irradiating uranium-238 with neutrons in a nuclear reactor, then recovered via nuclear reprocessing of the fuel. (L1840)"}]