Fig. 3. Dependence of Cu₃BTC₂ particle sizes on modulator equivalents. SEM images of particles synthesized with 7 modulator equivalents show globular morphology at (a) 33% and (b) 50% benzoic acid (BA), whereas (c) SEM shows octahedral particles when synthesized with 66% BA. Percentages indicate the mole fraction of BA, with the remainder added as sodium benzoate. (d) Dependence of size on modulator equivalents with varying benzoic acid content. Syntheses were performed with a linker : metal : modulator ratio of 3 : 1 : 21, where modulator corresponds to the sum of benzoic acid and sodium benzoate. The metal concentration was held constant (1 mM). The grey line at 7 equivalents shows the data used again in Fig. 4. Details of the synthetic conditions can be found in the Experimental methods and Tables S5–S7.†.