In my graduate school days, I synthesized a number of simple carbohydrates. One of the problems was getting the products to crystallize because carbohydrates are notorious for holding onto the water with which they have been in contact. As a result, they tend to form syrups instead of crystals. When attempting to study molecular structure using an instrumental method called nuclear magnetic resonance (NMR) spectroscopy, syrups won’t do.

The challenge was to rid the syrup of water and hope the residue would then crystallize. But how do you do that?

The first attempt usually is to place the syrup in a glass vessel called a “desiccator” that is attached to a vacuum pump and hope to draw the water away. I wasn’t successful with that.

Back in those pre-computer days, you went to the library and searched books and journals for an answer. It took a while, but I did locate a carbohydrate text that suggested placing phosphorus pentoxide in the desiccator (as an aside, I just asked ChatGPT the same question and in half a second, I got the same answer). The key is that this compound reacts with water to form phosphoric acid and pulls water out of the syrup.

Back to the lab I went, and it worked. The search that yielded phosphorus pentoxide kindled an interest in this compound.

I learned that it forms when phosphorus reacts with oxygen — in other words, when phosphorus burns. But there is an interesting nuance here. Phosphorus exists in two different forms, called........

© Montreal Gazette