Chemistry professors Doug Tobias and John Hemminger have an invited perspectives paper in the journal Science on Friday, Feb. 29, titled, "The Hofmeister Series: Getting More Specific about Specific Ion Effects." Different types of salt have predictable effects on a wide variety of chemical phenomena. For example, salt solutions containing fluoride ions tend to precipitate proteins, while salt solutions containing iodide ions dissolve them. These "specific ion effects" have been known for more than a century, but their molecular mechanism continues to evade scientists. This Science paper reviews recent progress toward unraveling specific ion effects, including research from the AirUCI Environmental Molecular Sciences Institute.