QSPR study of standard absolute entropies for gaseous organic compounds using novel molecular connectivity indexes and Ring parameter

► Variable atomic valence connectivity index δ′i, Ring parameter H, and variable molecular connectivity index χ′km were proposed. ► A good four-parameter model can be constructed from H and χ′km by using the best subsets regression analysis method. ► The MLR method can provide an accurate model for the prediction of the standard absolute entropies of gaseous organic compounds.