Dear Faldage: It would be nice of AHD had cited system in which gas goes directly to solid.
I'm prepared to believe it can happen, but I have never seen icicles grow.
Another example of sublimation that I remember involves crystals of iodine. I used to take
tincture of iodine, and add strong ammonia to it. Purple crystals of NI3 are fprmed. They
can be collected on a filter paper. They are harmless when wet, but when dry are violently
explosive. Trick was to spread wet crystals on floor. A few hours later anybody who stepped
on them got an alarming surprise. Janitor sweeping floor would get shell-shocked. The French
chemist who discovered the reaction lost a couple fingers learning about handling the product.
Would you call that a sublime explosion? Iodine crystals also sublimate slowly.