Extending Benson Group Increment Theory to compounds of phosphorus, silicon, and boron with computational chemistry

Abstract

A huge gap exists between the 200 million+ known chemical species listed in the Chemical Abstracts Service Registry and the few thousand compounds with data available in thermodynamic databases. In this work, high-level quantum chemical composite methods were applied to calculate thermodynamic properties for more than 300 compounds of phosphorus, silicon, and boron with little or no experimental data available. The acquired standard gas-phase enthalpies of formation, entropies, and heat capacities were compared to and contrasted with results from prior computational investigations as well as experimental studies. This revealed inconsistencies, outliers, and even systematic errors in the experimental data, with revised values suggested for thermodynamic properties of many fundamental small molecules. The data also enabled the derivation of new and updated group contribution values for almost 150 phosphorus-, silicon-, and boron-based groups within the framework of the Domalski-Hearing version of the Benson Group Increment Theory. These new values allow the thermodynamic properties of both existing and new chemical species of the three elements in question to be estimated quickly and inexpensively compared to the time and resources required if similar tasks were performed with quantum chemical methods of equal accuracy. Such advances in predictive methodology are highly valuable in many areas of chemical research and industry.