sentence: Chemists also count atoms when naming a sigmatropic shift where a hydrogen atom moves.
sentences_after: The carbon chain does not break in a hydrogen atom migration. So, chemists count across all atoms involved in the reaction rather than only across the closest atoms.
concept_name: chemist
headings: Sigmatropic reaction Overview of Sigmatropic Shifts Woodward-Hoffman Sigmatropic Shift Nomenclature
categories: Rearrangement reactions