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Data Formats for Elementary Gas Phase Kinetics: Part 1. Unique Representations of Species at the Molecular Level



Donald R. Burgess Jr., Jeffrey A. Manion, Carrigan J. Hayes


Standardized electronic formats for data are needed to efficiently and transparently communicate the results of scientific studies. A format for the unique identification of chemical species is a requirement in the field of chemistry, and the IUPAC International Chemical Identifier (InChI) has been widely adopted for this purpose. The InChI identifier has proved to be a very useful, but is currently insufficient to uniquely specify some types of molecular entities at a detailed molecular level needed to fully characterize their chemical nature, to differentiate between chemically distinct conformers, to uniquely identify structures used in quantum chemical calculations, and to completely describe elementary chemical reactions. To address this limitation, we propose an augmented form of InChI, denoted InChI–ER, which contains additional optional layers that allow the unique and unambiguous identification of molecules at a detailed molecular level. The new layers proposed herein are optional extensions of the existing InChI formalism and, like all other InChI layers, would not interfere with InChI identifiers currently in use. The focus of the present work is the better specification of required molecular entities such as rotational conformations and ring conformations. In a companion article, we propose additional reaction layers using an extended InChI format that will enable the unique identification of elementary chemical reactions including of bonding changes during the reactions, transition states, and classification of the types of chemical reactions.
International Journal of Chemical Kinetics


IUPAC, InChI, cheminformatics, molecular structure, electronic states, molecular conformations, chemical kinetics, transition states, reaction class, chemical species


Burgess, D. , Manion, J. and Hayes, C. (2014), Data Formats for Elementary Gas Phase Kinetics: Part 1. Unique Representations of Species at the Molecular Level, International Journal of Chemical Kinetics, [online], (Accessed April 21, 2024)
Created August 26, 2014, Updated November 10, 2018