For Zr12-butanoate and Zr12-octanoate, we find that the Zr12-acetate structure model gives a satisfactory fit (Figure ), which is clearly better than the refinement with a Zr6acetate structural model (Figure ). The latter structure was reported after crystallization from aqueous solution. In contrast, the Zr6-methylbutanoate cluster, is best described by the Zr6 model and gives a worse fit for the Zr12 model. The Zr12-oleate cluster was best described by the Zr12-propionate structure model with the slightly larger Zr-Zr distances.