RegEx for parsing chemical formulas

Question

I need a way to separate a chemical formula into its components. The result should look like this:

   Ag3PO4 -> [         


        

Answer 1

When you encounter a parenthesis group, you don't want to parse what's inside, right?

If there are no nested parenthesis groups you can simply use

[A-Z][a-z]*\d*|\([^)]+\)\d*

\d is a shorcut for [0-9], [^)] means anything but a parenthesis.

See demo here.