Actinide
The actinide series is the family of elements with atomic numbers 89 through 102. Actinium is the first in the series of actinides, and the family is named after it. 

The spaceborne organism nicknamed "", discovered by the  in 2367, had an outer shell made from silicates, actinides, and carbonaceous chondrite. ()

The asteroids of the Ikalian asteroid belt contained actinides, which provided protection from sensors. Ambassador  and Worf therefore deduced in 2367 that Kriosian rebels had to hide in that asteroid belt. ()

Actinides 

 #90 Thorium (Th)

 #92 Uranium (U)

 #94 Plutonium (Pu)

 #98 Californium (Cf)

External links 
 
 

cs:Aktinoidy
nl:Actinide
Elements