Beyond Brines: Iron-Based Ionic Liquids as Persistent Non-Aqueous Solvents on Mars

Perchlorate and chloride brines, while capable of transient liquid stability on Mars, rapidly lose their aqueous component under Martian pressure. Ionic liquids' negligible vapor pressures enable indefinite persistence, and they function without water activity constraints or chaotropic stress. Here we present the novel concept of iron-based ionic liquids as a complementary class of Mars-relevant solvent systems.We synthesized iron-based imidazolium ionic liquids and we showed that (i) month-long exposure to simulated Mars surface conditions (600 Pa, CO₂) produces negligible mass loss (