Flerovium

Flerovium is a synthetic, highly radioactive element first produced in a laboratory in 1999 by bombarding a plutonium target with calcium nuclei. Only a few atoms have been made, and they decay quickly, so scientists can study its chemistry only in specialized experiments. Experiments suggest that flerovium is highly volatile and may even be gaseous under ordinary conditions, while calculations predict some metallic character. Its bulk properties are not directly known, and it has no practical uses outside scientific research.