Polonium
The chemical element Polonium (Po), atomic number 84, is a silver-gray semi-metal. This highly radioactive element occurs in uranium ores.
Glossary Source
JRC EU CBRNe Glossary
(
EU Glossary on Chemical, Biological, Radiological, Nuclear, and Explosive risks
)
https://publications.jrc.ec.europa.eu/repository/bitstream/JRC128863/JRC128863_01.pdf