images by Wikimedia Commons
Having just come out of high school, I remember this chemical very well. Sulfur hexafluoride, plays a large part in Level 3 Structure and Bonding, in Chemistry. The bonding shape and angles make it a perfect candidate to display the octahedral shape etc.
Something that my chemistry professor neglected to mention was just how COOL this chemical is! Sulfur hexafluoride is much denser than air, and can act almost like a liquid, as seen in this video below where a boat made out of tinfoil floats on a layer of sulfur hexafluoride.
(suffering issues with the video showing, it will show if you view the post on the blog)