There is a chemical bond between two atoms or groups of atoms in the case
that the forces acting between them are such as to lead to the formation of
an aggregate with sufficient stability to make it convenient for the chemist
to consider it as an independent ‘molecular species’.
Molecule is the most important data structure in gchemol, which repsents
“any singular entity, irrespective of its nature, used to concisely express
any type of chemical particle that can exemplify some process: for example,
atoms, molecules, ions, etc. can all undergo a chemical reaction”. Molecule
may have chemical bonds between atoms.