where [A] is the precursor concentration, which we take here as the isopropoxide concentration. We report the rate constants k 1 and k 2 in Table along with the reaction half-life and the reaction end-point. The latter values are useful to design and plan syntheses. The error in k 1 is quite high (which is consistent with the literature ) and there is no statistically significant difference in k 1 between zirconia and hafnia. However, zirconia has a k 2 that is double compared to hafnia. The initial rate is one order of magnitude higher for titania compared to zirconia and hafnia. The decomposition of titanium isopropoxide goes to completion in just 3 minutes, which is 6 times faster than for Zr and 10 times faster than for Hf. Zirconium and hafnium are often considered twin metals with highly similar properties.