Next, we investigated the compounds with at least one incorrect functional group prediction (MPR = 0) provided in Listing S1. There are noticeable patterns of functional group types present in the set of failures. One example is nitro groups, which appear over 20 times in the failed compounds. This group is of interest as it is characterized by two strong bands which overlap with bending modes in alkane and amides functional groups. Many of these nitro compounds are misclassified as amides or alkanes and this observation partially explains the poor performance of amide functional groups shown in Figure . Although it is discouraging to note that the model was unable to 'ignore' these peaks, the low count of amides present in the dataset may attribute to this poor performance.