Science, Tech, Math › Science What Is the Strongest Acid? World's Strongest Acid Share Flipboard Email Print The strongest acids actually are not that corrosive!. Deven Dadbhawala / Getty Images Science Chemistry Chemical Laws Basics Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated May 05, 2019 What is the world's strongest acid? It's probably not one you'd guess. None of the strong acids traditionally listed in a chemistry text holds the title of World's Strongest Acid. The record-holder used to be fluorosulfuric acid (HFSO3), but the carborane superacids are hundreds of times stronger than fluorosulfuric acid and over a million times stronger than concentrated sulfuric acid. The superacids readily release protons, which is a slightly different criterion for acid strength than the ability to dissociate to release a H+ ion (a proton). The strongest carborane superacid has the chemical structure H(CHB11Cl11). Strong Is Different from Corrosive The carborane acids are incredible proton donors, yet they are not highly corrosive. Corrosiveness is related to the negatively-charged part of the acid. Hydrofluoric acid (HF), for example, is so corrosive it dissolves glass. The fluoride ion attacks the silicon atom in silica glass while the proton is interacting with oxygen. Even though it is highly corrosive, hydrofluoric acid is not considered to be a strong acid because it does not completely dissociate in water. The carborane acid, on the other hand, is highly stable. When it donates a hydrogen atom, a negatively charged anion left behind is sufficiently stable that it doesn't react any further. The anion is the carborane portion of the molecule. It consists of one carbon and a cluster of 11 boron atoms arranged into an icosahedron.