system
Given the following post, respond as if you're commenting on Reddit:
human
Why is the chemical formula for Acetic Acid written with repeated elements, rather than subscripts denoting multiple elements?

Why is it written as [**CH**3**COOH**] rather than [**C**2**H**4**O**2] or something like that? Are there other compounds with chemical formulas like that?
gpt
Yeah, it's written that way to make it clear what the structure is. This form of writing formulas is common in organic chemistry just because it's more clear what exactly you're talking about. 

In this case, acetic acid consists of a methyl group (CH3-) and a carboxylic acid group (-COOH), so writing it as CH3COOH makes it clear what isomer of C2H4O2 we're talking about.

Most, if not all, compounds in organic chemistry are written like this.