A friendly reminder regarding spoilers! At present the expanded Trek universe is in a period of major upheaval with the continuations of Discovery and Prodigy, the advent of new eras in gaming with the Star Trek Adventures RPG, Star Trek: Infinite and Star Trek Online, as well as other post-57th Anniversary publications such as the ongoing IDW Star Trek comic and spin-off Star Trek: Defiant. Therefore, please be courteous to other users who may not be aware of current developments by using the {{spoiler}}, {{spoilers}} OR {{majorspoiler}} tags when adding new information from sources less than six months old (even if it is minor info). Also, please do not include details in the summary bar when editing pages and do not anticipate making additions relating to sources not yet in release. THANK YOU
READ MORE
Actinium (symbol Ac) is a chemical element, atomic number 89 on the periodic table.
Actinium, in its most stable form, has an atomic mass of 227, and was discovered by Humans for the first time in France on Earth's European continent in the year 1899. This element is the first of the actinide series of heavy elements. (ST reference: Star Fleet Medical Reference Manual)