Atomistic simulation with a reactive force field of proton diffusion within a perovskite structured oxide. Reference: P. Raiteri et al, J. Phys. Cond. Matter, 23, 334213 (2011)

This shows stable pre-nucleation species formed by calcium and carbonate ions in solution (Ca = green, carbon = blue, oxygen = red). Reference: R. Demichelis et al, Nature Commun., 2, 590 (2011)