Re: What substances, other than dry ice, are able to sublimate?

All substances that are stable as gases can be made to go directly from solid to 
gas and to condense from gas to solid without going through an intermediate 
liquid phase. It is just a matter of having a low enough external pressure.

If you put some ice, well below freezing point, into a glass vacuum line, and you 
have another part of the vacuum line chilled by liquid nitrogen, the ice will 
sublime from its original place, and collect as ice crystals where the liquid 
nitrogen is, without ever getting wet. That is the basis of freeze drying, which 
is often used as a method of dehydration of such things as food substances.

So at low pressures, (almost) everything sublimes.

At ordinary atmospheric pressure there are quite a number of substances that pass 
directly from solid to gas when you warm them, and can be condensed back to solid 
without going through an intermediate liquid stage. But there are very few that 
do so at ordinary temperatures, or that are common enough that you would have 
come across them. One example is phthalic anhydride (1,2-benzenedicarboxylic acid 
anhydride), which is widely used for making paint resins. Another is terephthalic 
acid (1,4-benzenedicarboxylic acid), which is used form making polyester.

There are a couple of other substances that you might come across that **appear** 
to sublime, but are really undergoing chemical change, so it is not quite the 
same thing.

Ammonium chloride (smelling salts) seems to sublime if you warm it up, because 
what happens is

ammonium chloride (solid crystals) <--> ammonia (gas) + hydrogen chloride (gas)

and when the two gases come together in dry air, you get a thick white smoke 
forming  -- solid ammonium chloride being produced in the reverse of the above 
reaction.

Another similar one is metaformaldehyde, or 1,3,5-trioxane, which is used as 
snail bait. When you warm it, a metaformaldehyde molecule breaks up into 3 
ordinary formaldehyde molecules. Again, the reverse process can occur when 
formaldehyde cools in dry air.

C3H6O3 (metaformaldehyde -- solid) <--> 3 CH2O (formaldehyde -- gas)