Lanthanide elements are essential parts of today’s high-tech commodities including flat-screen TVs, cell phones, electric cars, and satellites. While the demand for these elements is high, separating lanthanides from impurities (other lanthanides) is extremely difficult. Industry uses liquid-liquid extraction. The target in water slips into an oil phase with the help of an extractant molecule. Impurities remain in the water. For decades, researchers have designed novel extractants. However, they’ve largely overlooked the subtle effects of the thin layers of water that come along for the ride, wrapped around the target. New research reveals peculiar arrays of water molecules affect how the extractant works.