Noun: protactinium ,prow,tak'ti-nee-um
- A radioactive metallic element formed from uranium and disintegrating into actinium and then into lead
"Protactinium was discovered in 1913 as a decay product of uranium";
- protoactinium [rare], Pa, atomic number 91
Derived forms: protactiniums
Type of: metal, metallic element
Encyclopedia: Protactinium