Lanthanide orbitals spring a reaction surprise

The lanthanide elements ’ 4f electron orbitals are notoriously shy and retiring, and they were long thought to be unwilling partners in chemical bonding. Now chemists have brought out a surprising extrovert streak in the orbitals, in what they believe is the first clear example of 4f bonding actually steering the course of a reaction ( Nat. Chem. 2025, DOI: 10.1038/s41557-025-01791-2). “As the evidence began to mount, I got really excited because I’ve been looking for something like this for basically my whole independent career,” says Eric J. Schelter of the University of Pennsylvania, part of the team behind the work. In principle, the discovery could help to develop lanthanide catalysts or reveal better ways to separate these critical elements . Found at the heavier end of the periodic table, the lanthanides are the first elements to carry electrons in their 4f orbitals. Chemical dogma suggests that these orbitals are