text: The way that porosity develops during the dealloying process has been studied computationally to understand the diffusional pathways on an atomistic level. Firstly, the less noble atoms must be dissolved away from the surface of the alloy. This process is easiest for the lower coordinated atoms, i.e., those bonded to fewer other atoms, usually found as single atoms sitting on the surface ("adatoms"), but it is more difficult for higher coordinated atoms, i.e., those sitting at "steps" or in the bulk of the material. Thus, the slowest step, and that which is most important for determining rate of porosity evolution is the dissolution of these higher coordinated less noble atoms. Just as the less noble metal is less stable as an adatom on the surface, so is an atom of the more noble metal. Therefore, as dissolution proceeds, any more noble atoms will move to more stable positions, like steps, where its coordination is higher. This diffusion process is similar to spinodal decomposition. Eventually, clusters of more noble atoms form this way, and surrounding less noble atoms dissolve away, leaving behind a "bicontinuous structure" and providing a pathway for dissolution to continue deeper into the metal.