In an attempt to correlate the vapor pressure of polychlorinated biphenyl compounds with their molecular structure, use was made of a number of topological indices. Included in our study were the Wiener index, W; the Balaban distance sum connectivity index; J; several of the Randić molecular connectivity indices, namely 0 χ through 2 χ, 3 χ p through 6χp, 3 χ c through 5 χ c, 4 χ pc through 6χpc and 6χCH (both simple and valence terms); and the chlorine number, n CI. Excellent correlations were obtained for two different temperatures, viz. 25°C and 100°C. It is demonstrated that the indices which correlate best at these two temperatures are in general not the same.
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