We next investigated the effect of raised temperature on a solution of HfCl4 in the same DFW 65:25:10 solvent. Since our previous work showed that hcp UiO-66(Hf), containing dodecanuclear metal clusters ("double cluster"), required higher synthesis temperatures compared to fcu UiO-66(Hf), which contains the hexanuclear single cluster, we studied our system at two temperatures: 150°C, the temperature used for our lab syntheses of hcp UiO-66(Hf) and hcp UiO-67(Hf), and 120°C, at which temperature hcp UiO-67(Hf) did not form. We also investigated the effect of the presence of additional coordinating linkers by performing reactions at the two different temperatures both with and without terephthalic acid (H2BDC) linker.