Fig. 1
From: Open-source QSAR models for pKa prediction using multiple machine learning approaches
a Six methods of measuring pKa were used for the 7912 DataWarrior chemicals. Only four chemicals had pKas measured by NMR, and five chemicals had kinetic measurements of pKa, thus those bars are not visible in the histogram. No information on the experimental method used to determine pKa was provided for 901 chemicals. b Distribution of the number of chemicals having averaged experimental values