Improvements from NBO Feature Engineering: The influence of NBO feature engineering on model performance is illustrated through comparison between the performance of the best Tdec and log(IS) models generated using the initial parameter set with the performance of the best models developed with the extended parameter set. A useful metric for the ability of a descriptor set to account for "charged" NBO structures is the comparison of the MAE obtained for the dominant natural Lewis structure and that of the charged set (Figure ). Our expanded suite of descriptors substantially reduced the difference in MAE between these two groups of tetrazoles for both the prediction of Tdec (30 to -7 °C) and log(IS) (0.13 to -0.02).