I can't figure out why this happens with pure substances. My book is a

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Curl
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I can't figure out why this happens with pure substances. My book is a piece of junk, perhaps someone could recommend a better book.

But why does water, for example, sublime below triple-point pressures?

If I'm below triple point pressure and I add energy to solid water, there should be a point where I can break the crystal bonds. But I just added enough energy to pay for the "latent heat" of fusion, not nearly enough for the enthlapy of vaporization.

So what happens? Does it remain a solid? How does that work, what happens to the energy I added? I don't see why the liquid phase is skipped.

Thanks for any help.
P.S. Wikipedia is worthless on this subject.
 
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Wow, honestly I didn't think this was such a tough question...
 


As far as enthalpies of fusion and vaporization, they're different for different temps and pressures, so I'm sure that the calculations go right if you use the enthalpies of the below-triple-point pressure and not the STP enthalpies.