Order of atoms in chemical formulas

[Mu naught]

what determines what order the atoms in a formula are written?

for example, why is it CO₂ and not O₂C?

It doesn't appear to be ordered by atomic weight, place on the peridoic table or alphabetically so what is it?

 

[Borek]

Consult IUPAC Red Book.

http://www.iupac.org/publications/books/rbook/Red_Book_2005.pdf

Be ready. That's not a reading for lighthearted.

You may start with section IR-2.15