) were over-represented by a factor of 6.05. We observed 5,805 descriptor pairs in at least two molecules in the set. As with singular descriptors, we compared the proportion of molecules displaying a descriptor pair in the set to the proportion of molecules displaying a descriptor pair in the total set (Equation ). These descriptor pairs and their over-representation factors are likewise included in Table . Six different descriptor pairs were tied as most over-represented in the set. For these, all molecules displaying these pairs in the total set were also included in the set. For example, there were five molecules characterized as both ketene acetal derivatives and oximes (