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

[Curl]

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.

 

[Curl]

Wow, honestly I didn't think this was such a tough question...

 

[Sakha]

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.