What is a two letter abbreviation for chemical measure?

Answer 1

About the only unit I can think of that it makes sense to describe as a specifically chemical measure is the mole, which is abbreviated mol. You'll notice rather quickly that this is three letters rather than two, so I have no idea what the question could be referring to.

Well, I have ideas, but the problem is that I have many of them. mg, kg, gr, dr, dm, lb, oz ... there are all kinds of abbreviations archaic and otherwise that a chemist MIGHT use (or might, around the 17th century, have used) for units of measurement. The problem is that, except for the aforementioned moles, most of them are not specifically chemical, and it's hard to narrow them down.

If this is from a crossword puzzle, it was almost certainly thrown in because of some awkward construction pairing up a couple of unlikely letters, since it's a terrible clue.