Quote:
Originally Posted by LJP07
I think we all agree that the Sulfur Hexafluoride one was absolutely cool amongst all cool things....
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Let's do some chemistry with it. The average molecular weight of air is 29. SF6 comes in at 146.60 or 5.10 times as dense as air . (A molar volume is a molar volume, 22.4 liters at STP.) Can we do better? Sure! Make something volatile by perfluorination and symmetry (removal of dipole moment). IF7. bp = 4.77 C, colorless gas. MW = 259.89 or 8.96 times as dense as air. It's smelly, reactive, and toxic. Can we do better? Sure!
US Patent 3992424. Take your perhalogenated whatsis-X, microwave plasma with F3C-CF3, swap partners to get whatsis-CF3 and CF3X. I(CF3)7 is perfectly reasonable and most likely gaseous at room temp or slightly above. MW = 609.95 or 21.03 times as dense as air. A two-liter bottle of air contains 2.6 grams of air (piffle) or 54.5 grams of I(CF3)7 - and that's perceptably heavy. U(CF3)6 is "a very volatile solid," MW = 652.
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Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz4.htm
