Actinium

Actinium is the first of the actinide series of elements. They are a separate set because the behavior of actinium was so similar to the rare earth elements, particularly lanthanum.

Actinium is very active, actually 150 times more so than radium. None of it's properties are stable. It was discovered by Andre Debierne in 1899 and is named from the Greek word for beam/ray.

Actinium is found in decaying uranium and can be prepared by reducing flouride within lithium vapor. Because of it's high activity level, it is good at producing neutrons but more importantly, it has been used in studies to help cure cancer.