Lanthanides: The Contraction and Why Separation Is So Hard
Inorganic Chemistry · f Block Lanthanides: The Contraction and Why Separation Is So Hard One structural fact — poor shielding by f electrons — explains the contraction, the similarity of the elements, and the difficulty of separating them. BSc & MSc · Inorganic Chemistry · Concept The short answer: Across the lanthanide series the 4f electrons shield the nuclear charge poorly, so the effective nuclear charge rises steadily and the ionic radius falls. That contraction makes the elements chemically almost identical, which is why they occur together and separating them requires methods exploiting very small differences. What the contraction is…