Tasks Even though many heuristics can be used to define the number of lone pairs, we argue that a data-driven model is more well-suited in this case since it can interpolate between different contexts. With this in mind, we built a neural network capable of predicting the number of lone pairs for each atom and their types. Such types were used to distinguish lone pairs of the same atom since there are possible differences in their NBO data. For that reason, we determined the types by an analytical threshold relating sand p-characters, expressing the conjugation likelihood of a given lone pair. The threshold is defined by the equation below: