FOOF: The Chemical Most Chemists Avoid
Dioxygen difluoride sounds rather harmless: just two of what you breathe and two of what's in your toothpaste. It even has an adorable, cushy nickname: FOOF. But most sane chemists know dioxygen difluoride is not a chemical to be trifled with.
An orange-yellow solid, dioxygen difluoride melts at 109.7K to an orange-red liquid. Note, that's Kelvin, not Celsius. That means FOOF melts at -262.2 °F! The chemical wouldn't even solidify on the coldest-known day on Earth, July 21, 1983, when the recorded temperature at the Soviet Vostok Station in Antarctica plummeted to −128.6 °F.
But a frigid melting point isn't the most exciting thing about FOOF. The most exciting thing is that it reacts violently with almost anything it comes into contact with, and by react, I mean explode. FOOF is one of the most furious oxidizers known to man -- it rips electrons from other compounds. Oxygen does the same thing to fuel combustion, but not quite so feverishly as FOOF.
Due to dioxygen difluoride's excitable nature, chemist Derek Lowe absolutely refuses to work with it, calling it "Satan's kimchi." He references a 1962 paper by one A.G. Streng as proof for his claim.
Streng was very likely the first chemist to explore and document FOOF's volatile nature. Though his report is characteristically dry, as one would expect for a paper published in the prestigious Journal of the American Chemical Society, its thesis is thrilling. As Streng discovered firsthand, FOOF explodes when mixed with just about everything, even at "cryogenic conditions." Derivatives of "violent," "vigorous," and "explosive" frequently appear throughout Streng's account of his experimental escapades, prompting the reader to wonder just how the man escaped with his life.
"If the paper weren't laid out in complete grammatical sentences and published in JACS, you'd swear it was the work of a violent lunatic. I ran out of vulgar expletives after the second page. A. G. Streng, folks, absolutely takes the corrosive exploding cake, and I have to tip my asbestos-lined titanium hat to him," Lowe remarked.
Fortunately (or unfortunately, depending upon how you look at it), you won't find FOOF in your run-of-the-mill chemistry lab. It requires storage below 100K, and can only be created by mixing fluorine and oxygen at very low pressures then running a current through the mixture, or by mixing the two elements in a stainless steel vessel at 77.1K, or by heating them at 1,300 °F and subsequently cooling the reactants with liquid oxygen.
If there's one thing to remember about FOOF, it's that it goes poof!