1. Molecules with chemical reaction: husband-wife relationship, lover relationship;

2. The relationship between similar molecules: the relationship between relatives and friends, the same smell, birds of a feather flock together, people are divided into groups;

3. The relationship between molecules with great differences: the relationship between enemies, the voice of chickens and dogs is endless, and there are still some traitors or non-mainstream, that is to say, absolute incompatibility does not exist.