Trophy molecule breakthrough for Nottingham scientists  

Experts at The University of Nottingham have created a stable version of a ‘trophy molecule’ by preparing a terminal uranium nitride compound which is stable at room temperature and can be stored in jars in crystallised or powder form.

The breakthrough could have future implications for the nuclear energy industry — uranium nitride materials may potentially offer a viable alternative to the current mixed oxide nuclear fuels used in reactors.

The research* was led by Dr Stephen Liddle in the School of Chemistry, with much of the practical work completed by PhD student David King and supported by colleagues at the University of Manchester.

Dr Liddle said: “The beauty of this work is its simplicity — by encapsulating the uranium nitride with a very bulky supporting ligand, stabilising the nitride during synthesis with sodium, and then sequestering the sodium under mild conditions we were able to at long last isolate the terminal uranium nitride linkage.”

He added: “A major motivation for doing this work was to help us to understand the nature and extent of the covalency in the chemical bonding of uranium. This is fundamentally interesting and important because it could help in work to extract and separate the 2 to 3 per cent of the highly radioactive material in nuclear waste.”

The work was supported by the UK National Electron Paramagnetic Resonance (EPR) Facility, funded by the Engineering and Physical Sciences Research Council and based in the Photon Science Institute at The University of Manchester. The uranium-nitride contains an unpaired electron and by using EPR spectroscopy it was found that it behaves differently from similar compounds prepared at Nottingham.

The research has been funded and supported by the Royal Society, European Research Council, the EPSRC, and the UK National Nuclear Laboratory.

*Reported in Science