Acetic acid, $$\(\mathrm{HC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}\)$$, is a commonly used weak acid, which is also an organic compound. This acid, and many other organic acids, own their acidic behavior to a specific structure of a particular group of atoms. What is the one way of writing the general formula of this particular group of atoms?

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