A team of scientists at King’s College London has identified a new form of aluminum, one of the most abundant metals on Earth, that could offer a far less expensive and more sustainable alternative to widely used rare earth metals.
Led by Dr. Clare Bakewell, a Senior Lecturer in the Department of Chemistry, the researchers created highly reactive aluminum molecules capable of breaking some of the strongest chemical bonds. Their findings, published in Nature Communications, also reveal entirely new molecular structures, opening the door to previously unknown types of chemical behavior.
Discovery of a Unique Aluminum Structure
The researchers reported the first known example of a cyclotrialumane, a compound made of three aluminum atoms arranged in a trimeric — triangular — structure. This unusual configuration shows remarkable reactivity. Importantly, the structure remains intact even when dissolved in different solutions, giving it the stability needed for a variety of chemical reactions.
These reactions include splitting dihydrogen and enabling the step-by-step insertion and chain growth of ethene, a simple 2-carbon hydrocarbon. Such capabilities highlight the compound’s potential for building more complex molecules.
Replacing Expensive and Scarce Metals
Metals play a central role in producing both everyday and specialized chemicals used across industry. Many of these processes rely on precious metals like platinum, which are costly and can have significant environmental impacts due to extraction.
Scientists have been searching for alternatives that are easier to obtain and more sustainable. Dr. Clare Bakewell explained: “Transition metals are the workhorses of chemical synthesis and catalysis — but many of the most useful are becoming increasingly difficult to access and extract — often being located in regions of political instability, increasing the demand and price.
“Chemists have been looking towards more common elements from the periodic table, and we chose aluminum, as it’s super abundant, making it ~20,000 times less expensive than precious metals such as platinum and palladium.”
Expanding the Possibilities of Aluminum Chemistry
In addition to designing aluminum compounds for use in chemical synthesis, the team is uncovering entirely new reactions.
Dr. Bakewell said, “What’s special about this work, is that we’re pushing the boundaries of chemical knowledge. Most excitingly, we can use this aluminum trimer to build completely new compounds with levels of reactivity that have never been observed before — these include the 5- and 7-membered aluminum and carbon rings formed through reaction with ethene. These capabilities go beyond the transition metals we were originally trying to mimic, to the forefront of chemical research.”
This emerging chemistry could allow scientists to develop new reaction types or assemble larger molecular structures with distinctive properties, potentially leading to new materials and products.
Toward Cleaner and Cheaper Chemical Production
Bakewell emphasized that the research is still in its early stages but shows significant promise.
She said, “we’re very much in the exploratory phase and we’re just at the start of beginning to unlock the capability of these earth-abundant materials.
“But from what we’ve seen already, this chemistry could support a transition to cleaner, greener and cheaper chemical production, whilst making new discoveries along the way.”