Oxychlorides Stable to −450°F, Offer Promise for Clean Energy

Researchers report that three rare-earth oxychlorides—NdOCl, YOCl and TmOCl—remain thermodynamically stable across an unusually wide temperature range, from 0 K (about −460°F) up to 500 K (about 440°F).\n\nThe team measured heat capacity over that span to derive enthalpy, entropy and free energy of formation, key thermodynamic parameters used to predict chemical stability, reaction energetics and behavior under varying temperatures and pressures. Those properties are directly relevant to proposed applications such as chloride ion conduction, energy storage and catalysis, and to the design of advanced electronic and magnetic components.\n\nTmOCl displayed a low-temperature Schottky anomaly in heat capacity, a signature that points to discrete electronic level splittings and could inform low-temperature device engineering.\n\nAuthors say these baseline thermodynamic data help evaluate material performance and reaction pathways, and support efforts to develop functional devices and more robust domestic rare-earth sources. Richard Riman notes that most rare-earth supply currently comes from China, and improving domestic production would reduce supply-chain risk and help manufacturers ensure reliable production and pricing.