Nomenclature, Chemical Abstracts Service Numbers, Isomer Enumeration, Ring Strain, and Stereochemistry: What Does Any of This Have to Do with an International Chemical Disarmament and Nonproliferation Treaty?

The Chemical Weapons Convention (CWC) is an international disarmament and nonproliferation treaty that mandates a comprehensive ban on chemical weapons. This treaty entered-into-force in 1997 and has a nearly universal membership of world states. The CWC provides definitions for what constitutes a chemical weapon and describes chemicals for which verification measures and regulatory oversight are required. These chemicals, which must be declared to the Organisation for the Prohibition of Chemical Weapons for verification purposes, appear in three Schedules within the CWC. The Schedules list specific chemical substances and families of chemicals defined by molecular structure descriptions that allow a range of specified variable groups. The text of an international treaty provides a basis for laws and regulatory requirements at international and national levels that must be enacted t , comply with treaty obligations. These laws and regulations must account for the "chemistry" that is described in the treaty text, which has been negotiated and agreed upon by world governments. In this paper, we look at some of the chemicals described within the CWC and discuss how atoms and molecules, nomenclature, and Chemical Abstracts Service numbers, isomer enumeration, ring strain, and stereochemistry influence the obligations of States to an international treaty. The material draws upon the authors' experiences from an interactive "Science for Diplomats" initiative that has provided a forum for engaging with chemical disarmament decision-makers to aid in their understanding of fundamental concepts in chemistry that have an impact on treaty implementation. We hope this article will spark interest from chemistry students and educators in the provision of science advice for policymakers and provide policymakers with an appreciation of the complexity and importance of understanding the language of chemistry in support of a world free of chemical weapons.