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

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