All actinides are radioactive and release energy upon radioactive decay; naturally occurring uranium and thorium, and synthetically produced plutonium are the most abundant actinides on Earth. Source: Internet
Another possible way to separate the trivalent actinides is via solvent extraction chromatography using bis-(2-ethylhexyl) phosphoric acid (abbreviated as HDEHP) as the stationary organic phase and nitric acid as the mobile aqueous phase. Source: Internet
Compared to the lanthanides, which (except for promethium ) are found in nature in appreciable quantities, most actinides are rare. Source: Internet
Coordination numbers are normally between two and nine, but large numbers of ligands are not uncommon for the lanthanides and actinides. Source: Internet
All but one of the actinides are f-block elements, corresponding to the filling of the 5f electron shell ; lawrencium, a d-block element, is also generally considered an actinide. Source: Internet
Americium is relatively soft and easily deformable and has a significantly lower bulk modulus than the actinides before it: Th, Pa, U, Np and Pu. Source: Internet