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A question came in my test asking which of the compounds are not stored in glass. The answers were $\ce{HF},$ $\ce{XeF6},$ $\ce{XeF4},$ $\ce{XeF2}$.

I know about $\ce{HF}$ and $\ce{XeF6},$ but not about the other two. As far as I remember, xenon does not have any oxide or oxyfluoride in the $+4$ and $+2$ oxidation state.

Is the given answer correct, and if so, what are the reactions involved?

andselisk
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Shubhraneel Pal
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    Interestingly, when a professor brought a small amount of $\ce{XeF2}$ into the lecture hall to pass around as a demonstration, I recall it being in a glass vial. However, if it was he could have just filled it into a glass one from a plastic one to prevent the plastic smell from obstructing the $\ce{XeF2}$ smell. – Jan Dec 19 '18 at 14:34
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    @Jan - it isn't like adding some HF to a glass bottle will instantly dissolve the glass. Similarly, the glass will probably last just fine with a bit of gas in it. – Jon Custer Dec 19 '18 at 16:41
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    @JonCuster XeF2 isn't gas in r.t.. Also it shouldn't attack glass unless there's been for ex. significant hydrolysis or high temp. – Mithoron Dec 19 '18 at 23:37

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Firstly I'll note the title and the body of the question ask slightly different things; just because substance X doesn't react with glass doesn't mean substance X should be stored in glass.

As far as I can tell $\ce{XeF4}$ and $\ce{XeF2}$ don't react with glass, at least not quickly. Greenwood and Earnshaw says of $\ce{XeF6}$, when comparing it with the other two fluorides, "the compound cannot be handled in glass or quartz because of a stepwise reaction" (see Why is xenon hexafluoride not stored in glass?). Housecroft and Sharpe says "At 298K $\ce{XeF6}$ reacts with silica (preventing the handling of $\ce{XeF6}$ in silica apparatus) ... while $\ce{XeF2}$ and $\ce{XeF4}$ do so only when heated". So it appears the lower halides do not react with glass at s.t.p.

Whether they should be stored in glass depends, I am guessing, upon the importance of hydrolysis by water in the atmosphere; this forms HF which will attack the glass. I can't answer this - I only mix compounds in computers.

Note an oxide of Xenon is known in the +4 state (see https://en.wikipedia.org/wiki/Xenon_dioxide) as is at least one oxyfluoride (https://en.wikipedia.org/wiki/Xenon_oxydifluoride)

Ian Bush
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