Benson group additivity values of phosphines and phosphine oxides: Fast and accurate computational thermochemistry of organophosphorus species

Composite quantum chemical methods W1X‐1 and CBS‐QB3 are used to calculate the gas phase standard enthalpy of formation, entropy, and heat capacity of 38 phosphines and phosphine oxides for which reliable experimental thermochemical information is limited or simply nonexistent. For alkyl phosphines and phosphine oxides, the W1X‐1, and CBS‐QB3 results are mutually consistent and in excellent agreement with available G3X values and empirical data. In the case of aryl‐substituted species, different computational methods show more variation, with G3X enthalpies being furthest from experimental values. The calculated thermochemical data are subsequently used to determine Benson group additivity contributions for 24 Benson groups and group pairs involving phosphorus, thereby allowing fast and accurate estimations of thermochemical data of many organophosphorus compounds of any complexity. Such data are indispensable, for example, in chemical process design or estimating potential hazards of new chemical compounds. © 2018 Wiley Periodicals, Inc. Experimental determination of thermochemical parameters is not always practical or required. While high‐level quantum chemical methods offer an important alternative, their use is not always feasible either. For large molecules, group additivity approaches represent the best approach to estimate thermochemical data of near chemical accuracy. A set of group contribution values is determined for phosphines and phosphine oxides, enabling the rapid application of Benson group additivity method to thermochemistry of many organophosphorus species.