Rare Goldilocks chemistry

Rare are the chemicals and rare too are the chemists who work with uranium and other actinides. Now, Stephen Liddle of the University of Nottingham, UK, and colleagues have for the first time isolated stable crystals of the triple-bonded nitride of uranium in the VI oxidation state. Liddle's strategy is something of a Goldilocks story: What I have found with uranium is that if something is going to work, it will work really well, or else it will not work at all, he seems. There seems to be very little middle ground. The key is to have everything just right. Building on their earlier work with uranium(V), the team used a bulky ligand and chemistry to trap a single nitrogen atom from an azide and then to use iodine to take a negative charge leaving the caged uranium(VI). This is fundamental chemistry but may have implications for the future handling of nuclear waste