Color key: green, uranium; black, carbon; blue, nitrogen; orange, silicon; hydrogen atoms omitted for clarity.
Image Credit: Courtesy of University of Manchester
Scientific Frontline: Extended "At a Glance" Summary: Isolable Uranium-Carbon Triple Bond
The Core Concept: A uranium Fischer-type carbyne, representing the first stable and isolable compound where a uranium atom forms a triple bond with a carbon atom.
Key Distinction/Mechanism: Unlike transition-metal carbynes which are well-established, this compound demonstrates two-way electron sharing involving actinides; carbon donates two electrons to the uranium, while uranium donates electrons back to the carbon via two orthogonal one-electron bonds.
Origin/History: Synthesized and characterized by an international team of researchers from Germany and the UK, including chemists from The University of Manchester, and published in Nature Chemistry in October 2026. Prior examples were only observed under highly specialized, non-isolable conditions (e.g., inside fullerene cages or at extreme low temperatures).
Major Frameworks/Components:
- Uranium precursor and a novel carbon-atom transfer reagent.
- Single-crystal X-ray diffraction, spectroscopy, and magnetometry for characterization.
- Quantum crystallography to visualize the 2.379(15) Å bond length and confirm the triple-bond interaction.
- Fischer-type carbyne interaction specific to f-element chemistry.
Branch of Science: Inorganic Chemistry, Actinide Chemistry, Radiochemistry.
Future Application: The novel carbon-atom transfer strategy provides a new synthetic toolkit to build previously inaccessible uranium compounds and related actinide systems.
Why It Matters: It addresses a longstanding challenge in heavy-element chemistry, providing a stable reference point to understand how f-block elements engage in multiple bonding, helping to integrate actinide behavior into the broader periodic table framework.
In a study published in Nature Chemistry, an international team of researchers from Germany and the UK, including chemists from The University of Manchester, has synthesized and characterized what the researchers describe as the first isolable uranium Fischer-type carbyne, a compound where carbon forms an unusual triple-bond interaction with uranium.
The findings give researchers a clearer example of how uranium can form multiple bonds with carbon, providing a new reference point for comparing the chemistry of actinides with more familiar transition metals. The discovery also demonstrates a new way of building previously inaccessible uranium compounds, expanding the toolkit for studying heavy-element chemistry.
Showing That Uranium Can Form a Rare Carbon Bond
Metal–carbon triple bonds are well established in transition-metal chemistry, but creating an equivalent uranium compound stable enough to isolate and study has proved much more challenging. Until now, related uranium examples had only been observed under highly specialized conditions, such as at extremely low temperatures or when trapped inside hollow carbon molecules known as fullerene cages.
The team, including Professor Stephen Liddle, John Seed, Ashley Wooles, Floriana Tuna, and Adam Brookfield, used a new synthetic strategy combining a uranium precursor with a recently developed carbon-atom transfer reagent, enabling them to create the compound and study it in detail.
To confirm the discovery, the researchers used single-crystal X-ray diffraction, spectroscopy, magnetometry, and advanced computational analysis. Together, these methods showed that the new compound has the key features expected for a Fischer-type carbyne.
“This work addresses a long-standing challenge in f-element chemistry. By isolating and studying this compound in detail, we have been able to show that uranium can support a Fischer-type carbyne interaction that is related to, but distinct from, those previously established for transition metals. The result expands our understanding of how uranium engages in multiple bonding with carbon and provides a foundation for exploring new areas of actinide chemistry.” —Steve Liddle, Professor of Inorganic Chemistry and Co-director of the Center for Radiochemistry Research
The team’s measurements showed that the uranium and carbon atoms sit 2.379(15) Å apart from each other. In chemical structures, shorter distances are usually needed to have multiple bonding, but in this case, quantum crystallography was used to visualize and confirm the uranium–carbon triple-bond interaction. Further analysis showed that this bond is formed through two-way electron sharing: carbon donates two electrons to uranium, while uranium also donates electrons back to carbon, in this case with two orthogonal one-electron bonds, which is rare.
The compound was also found to be relatively unreactive, which is what chemists would expect for this type of Fischer carbyne. Additional experiments showed that the bonding could be changed through chemical reduction, giving the team further evidence for how the compound’s electrons are arranged.
Why the Discovery Matters
The findings are primarily important for fundamental chemistry. They provide researchers with a clearer picture of how uranium forms bonds with carbon and help place actinide chemistry within a broader understanding of how elements behave across the periodic table.
The work also highlights the potential of modern carbon-atom transfer reagents to create compounds that were previously difficult or impossible to access, potentially enabling future studies of uranium–carbon bonding and related actinide systems.
Dr. John Seed, Research Fellow at The University of Manchester, said, “This study provides a platform for exploring new uranium–carbon bonding chemistry. Understanding how these interactions work will help us place actinide chemistry in a broader context and could guide future efforts to design related compounds.”
Published in journal: Nature Chemistry
Title: A crystalline uranium Fischer-type carbyne
Authors: John A. Seed, Jhen-Kuei Yu, Florian Meurer, Adam Brookfield, Floriana Tuna, Ashley J. Wooles, Michael Bodensteiner, Max M. Hansmann, and Stephen T. Liddle
Source/Credit: University of Manchester | Enna Bartlett
Edited by: Scientific Frontline
Reference Number: chm100226_01