Highlights

• Argonne National Laboratory researchers uncovered the molecular interactions that make lanthanide separation challenging.
• The study found lighter lanthanide elements form stronger bonds with extractants, challenging previous separation assumptions.
• Research could reduce processing costs and decrease dependence on Chinese rare earth refinement.

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A team of scientists led by Michael Servis, PhD (opens in a new tab), of the U.S. Department of Energy’s Argonne National Laboratory (opens in a new tab), has revealed the molecular “choreography” that underpins one of the most challenging steps in the rare earth supply chain: lanthanide separation. The findings, published in Chemical Science, offer fresh insights into how molecules arrange themselves around lanthanide ions during solvent extraction — a discovery with potential to transform the economics and efficiency of rare earth processing.

Study Summary & Findings

Lanthanides — critical components of magnets, catalysts, and medical imaging devices — are notoriously difficult to separate due to their chemical similarities. The Argonne team combined advanced simulations with experimental validation to map how extractant molecules, water, and competing ions interact with different lanthanide elements.

Their findings overturn conventional wisdom. Whereas traditional systems often favor heavier lanthanides, the Argonne group discovered that lighter elements such as lanthanum and europium form stronger, more stable bonds with extractants, while heavier lanthanides like lutetium face greater molecular “crowding.” The study also highlighted the underappreciated role of water molecules, which stabilize the lanthanide-extractant interactions through hydrogen bonding and open up new separation pathways.

Argonne National Laboratory

This molecular-level view provides the basis for designing more selective and efficient separation systems, potentially reducing costs, energy demands, and waste in rare earth processing.

Implications

If scaled, these insights could help unlock U.S. and allied rare earth deposits by making separation less capital- and reagent-intensive. For industry, this research suggests that solvent systems could be tailored to prioritize specific lanthanides depending on downstream demand — for example, neodymium and praseodymium for permanent magnets. Strategically, improved separation efficiency reduces reliance on Chinese refining dominance and aligns with Department of Energy and Department of Defense supply-chain resilience goals.

Limitations

The study remains at the molecular modeling and laboratory scale. Industrial separation involves additional complexities such as ore variability, impurities, and solvent degradation over time. Moreover, while the simulations offer predictive power, real-world performance will depend on pilot-scale validation and techno-economic analysis. As Servis himself acknowledged, the next step will be to test a broader range of extractants and solvents under operational conditions.

Conclusion

This Argonne-led study represents a breakthrough in fundamental rare earth chemistry, providing industry and policymakers with a scientific foundation to reimagine separation. While further work is needed to translate molecular insights into industrial practice, the research underscores the value of basic science in addressing global critical-mineral bottlenecks.

Citation: Servis M., Wang X., Peroutka A., Kravchuk D., Wilson R., Shafer J. A molecular dance in rare earth element chemistry: Revealing the molecular choreography behind lanthanide separation (opens in a new tab). Chemical Science. September 29, 2025.

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