Science, Tech, Math › Science Sulfur Hexafluoride Chemistry Demonstrations Fun Chemistry Demonstrations With an Anti-Helium Gas Share Flipboard Email Print Sulfur hexafluoride is non-toxic, colorless, non-flammable and six times heavier than air. You can float a light boat on the invisible gas. Mark Airs / Getty Images Science Chemistry Projects & Experiments Basics Chemical Laws Molecules Periodic Table 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 August 09, 2019 Sulfur hexafluoride is a non-toxic, invisible gas that you can use to perform interesting chemistry demonstrations. Breathe it in and make your voice much deeper when you talk. Pour it into a container and float an airplane or a ship on 'nothing'. In a way, it is like the anti-helium gas, because while helium is about six times lighter than air, sulfur hexafluoride is six times heavier. Sulfur Hexafluoride Facts Inorganic compound with a chemical formula SF6Non-polar gasNon-toxic, odorless, colorlessnNn-flammable at room temperature and pressureOctahedral geometryPoorly soluble in water; soluble in nonpolar organic solventsDensity of 6.13 g/L at sea level Fun Things to Try with Sulfur Hexafluoride Float Your Boat: Pour sulfur hexafluoride into an aquarium or large beaker. It is heavier than air, so it will sink. You can float light objects on the invisible gas, such as a paper airplane or a boat made from aluminum foil. If you use a cup to scoop up some of the sulfur hexafluoride and dump it into a foil boat, you can sink it.Talk or Sing with a Deep Voice: Sulfur hexafluoride is denser than air, so sound travels through it more slowly. If you breathe in a lungful of sulfur hexafluoride, your voice will become much deeper. Even though sulfur hexafluoride is non-toxic, you need to use care when performing this demonstration to avoid hypoxia and fainting (the same caution applies to helium). Don't breathe the gas for prolonged periods of time. Where You Can Get Sulfur Hexafluoride Sulfur hexafluoride is a specialty gas, used in medicine for eye surgery and ultrasound imaging; in industry as a tracer gas, dielectric, and as an etchant; and mixed with argon as an insulator between layers of windows. It has enough uses that you may be able to find it at a store that sells specialty gasses (try the yellow pages), such as oxygen, argon, and nitrogen.