# Formulae distinguished only by case [closed]

A recent question (on $$\ce{CI}$$ v $$\ce{Cl}$$) reminded of this question: are there any real (as opposed to contrived) formulae which would be the same if case was ignored?

One certain example is $$\ce{Co}$$, Cobalt, and $$\ce{CO}$$, Carbon Monoxide. Of course, confusing Cobalt and Carbon Monoxide is rather unlikely.

In my search for others, the best example I could find was $$\ce{BaS}$$, Barium Sulphide, and $$\ce{BAs}$$, Boron Arsenide. Are these real substances and is the stoichiometry just $$1:1$$? I had trouble verifying that.

Are there any more interesting examples?

One real example that I saw once was a poster in a university chemistry lab showing some complex organic molecules. $$\ce{Ac}$$ appeared at many points but it seemed very unlikely that these compounds contained Actinium. I then noticed $$\ce{Me}$$ and $$\ce{Et}$$ and guessed that they were organic units e.g. methyl and ethyl so $$\ce{Ac}$$ may have been acetyl.

## closed as too broad by Mithoron, user55119, Tyberius, Todd Minehardt, Gaurang TandonDec 3 '18 at 3:21

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

• Well, this is a legitimate concern indeed, which is why we feel irate to no end when somebody messes up cases in chemical formulae. – Ivan Neretin Nov 26 '18 at 13:29
• BaS is indeed a known compound, with the NaCl prototype. BAs is also a known compound with the ZnS prototype. – Jon Custer Nov 26 '18 at 19:53
• Well I never put it together that actinium acetyl have the same abbreviation. – A.K. Nov 27 '18 at 3:53