Specifications: Actinium Actinium is a chemical element with the symbol Ac and atomic number 89. Actinium is a silvery, radioactive, metallic element. Due to its intense radioactivity, actinium glows in the dark with a pale blue light. Actinium is found only in traces in uranium ores as 227Ac. One ton of uranium ore contains about a tenth of a gram of actinium. 235U (or 239Pu) is the parent isotope of the actinium series decay chain which ends with the stable isotope 207Pb.
