The crystal dimensions were varied by changing the concentration. As discussed above, the range of Cu(NO3)2 from 0.25 mM to 0.86 mM (metal-to-ligand ratio: 0.17:1  0.57:1) resulted in flower-like crystals with six petals having the lowest concentration of crystals having a dendritic appearance. The overall dimensions vary from 45 µm to 14 µm (Figure ). Increasing the concentration of Cu(NO3)2 (metal-to-ligand ratio: 1:1  6:1), while maintaining all other parameters fixed, resulted in monodisperse hexagonal prisms. The excess of metal salt appears to affect the nucleation with a concomittent increase in the number of crystals. It is an accepted fact that a larger number of nucleation sites results in smaller crystals. These hexagonal prisms become smaller as the concentration of Cu(NO3)2 increases. The dimensions for this series of crystals decreases from h = 8 µm to 1 µm and w = 17 µm to 2 µm, respectively (Figure ). Despite these large changes in size, the aspect ratio (h/w) remains unchanged (~0.5). PXRD measurements reveal that the crystallographic packing remains similar (Figure ) for the different morphologies shown in Figure .