Keywords: 
• chlorinated phenolic compounds /
• toxicity (-lgIC₅₀) /
• structural descriptor /
• structure and activity relationship (QSAR)

Abstract: New structural descriptors were obtained through parameterization of the different non-hydrogen atoms and the relationship between them in organic molecules. Then the molecular structures of some chlorinated phenolic compounds were characterized by the structural descriptors. The partial least squares regression (PLS) method was used to construct a model of relationship between the structures and toxicity (-lgIC₅₀) of chlorinated phenolic compounds. The modeling correlation coefficient (R²) was 0.948, the "leave one out" cross validation correlation coefficient (Q²) was 0.922 and the standard deviation (SD) was 0.184, respectively. The results showed that the structural descriptors could well characterize the molecular structures of the compounds, the stability of the model was good, and the predictive power was strong. This study shows a certain reference value for QSAR study of phenolic compounds.