The rule-based strategy is applied only to reactions that are carbon-balanced. The reason is that in organic reactions, the structure of the carbon backbone plays a key role, and thus, sum formulas are much less likely to be sufficient to completely describe the missing molecules. We also optimized our approach by considering the standard representation of ions in chemical equations, such as OH -and H + , instead of NaOH or HCl. To achieve this, we restructured our rule library to focus on elementary ions, enabling us to interpret compounds such as HCl in terms of their constituent ions, H + and Cl -. This refinement led to a more efficient and compact rule library, as depicted in Table .