Order of atoms in chemical formulas

Thread starter Mu naught
Start date Sep 4, 2010
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Atoms Chemical Formulas

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The order of atoms in a chemical formula is primarily determined by established conventions set by the International Union of Pure and Applied Chemistry (IUPAC). These conventions prioritize the order based on the nature of the elements involved, often favoring the more electropositive elements (those that tend to lose electrons) to be listed first. For example, in CO2, carbon (C) is more electropositive than oxygen (O), which is why it appears first. The order is not based on atomic weight, periodic table position, or alphabetical arrangement. The IUPAC Red Book provides detailed guidelines on these conventions, emphasizing the importance of systematic naming and formula writing in chemistry. Understanding these rules is crucial for clear communication in scientific contexts.

Sep 4, 2010

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?

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Sep 4, 2010

Borek

Mentor

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

Last edited by a moderator: May 4, 2017

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