Chemical substance identity of benzene, until the correct structure was described by Friedrich August Kekulé. Likewise, the idea of stereoisomerism – that atoms have rigid three-dimensional structure and can thus form isomers that differ only in their three-dimensional arrangement – was another crucial step in understanding the concept of distinct chemical substances. For example, tartaric acid has three distinct isomers, a pair of diastereomers with one diastereomer forming two enantiomers. An element is a chemical substance made up of a particular kind of atom and hence cannot be broken down or transformed by a chemical reaction into a different element, though it
Systematic name with or without numerical prefixes; e.g. pentane, oxazole." However, when trivial names have become part of chemical nomenclature, they can be the systematic name of a substance or part of it. Examples for some systematic names that have trivial origins are benzene (cyclohexatriene) or glycerol (trihydroxypropane). There are standardized systematic or semi-systematic names for: Systematic name A systematic name is a name given in a systematic way to one unique group, organism, object or chemical substance, out of a specific population or collection. Systematic names are usually part of a nomenclature. A semisystematic name or semitrivial name is a name