Krypton difluoride

<p>Krypton difluoride, KrF2 is a chemical compound of <a href="/facts/Krypton/llkNlCke">krypton</a> and <a href="/facts/Fluorine/YUV0Fb8m">fluorine</a>. It was the first <a href="/facts/Chemical_compound/37FXqqtv">compound</a> of krypton discovered. It is a <a href="/facts/Volatility_(chemistry)/90r3ep6w">volatile</a>, colourless solid at room temperature. The structure of the KrF2 molecule is linear, with Kr−F distances of 188.9 pm. It reacts with strong <a href="/facts/Lewis_acid/qlLqRvg2">Lewis acids</a> to form salts of the KrF+ and Kr2F+3 <a href="/facts/Cation/wrbwhF3z">cations</a>.  
</p><p>The atomization energy of KrF2 (KrF2(g) → Kr(g) + 2 F(g)) is 21.9 kcal/mol, giving an average Kr–F bond energy of only 11 kcal/mol, the weakest of any isolable fluoride.  In comparison, the dissociation of difluorine to atomic fluorine requires cleaving a F–F bond with a bond dissociation energy of 36 kcal/mol.  Consequently, KrF2 is a good source of the extremely reactive and oxidizing atomic fluorine.  It is thermally unstable, with a decomposition rate of 10% per hour at room temperature.  The formation of krypton difluoride is endothermic, with a heat of formation (gas) of 14.4 ± 0.8 kcal/mol measured at 93 °C.
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Krypton difluoride open-in-new

Krypton difluoride