Representative SEM images monitoring the transformation of microparticles 2a to crystalline rods 3a. (a) Particle 2a grown from the precursor solution, (b) early intermediate (5 min), (c) intermediate at a later stage (30 min), (d) crystalline rods 3a, (e) particle grown by first dissolving the crystalline rods 3a with pyridine and then exposing to ether by vapor diffusion, and (f) crystalline products 3a grown from the pyridine precursor 1a solution, Ni(OAc)2·4H2O, and methanol.