KnowraStructural isomerStructural isomerA molecule that shares a molecular formula with another molecule but differs in which atoms are bonded to which.BriefConnectMolecular formula: A notation showing the types and numbers of atoms in a molecule. Structural isomers share this atom count despite having different bonds.Chain isomerism: A form of structural isomerism in which the carbon skeletons have different arrangements. Branched and unbranched carbon frameworks are a common connectivity change.Butane: A four-carbon alkane with an unbranched carbon chain. It shares the formula C₄H₁₀ with the branched isomer 2-methylpropane.IUPAC nomenclature: A systematic method for naming chemical compounds using rules established by the International Union of Pure and Applied Chemistry. Systematic names distinguish compounds with the same formula but different structures.Chemical bond: An interaction that holds atoms together in molecules and other substances. Changing which atoms are bonded defines structural isomerism.Position isomerism: A form of structural isomerism in which a functional group or substituent occupies a different position. The same group can attach at different sites on an otherwise similar framework.2-Methylpropane: A branched four-carbon alkane, also called isobutane. Its branched skeleton contrasts with the unbranched structure of butane.Mass spectrometry: An analytical technique that measures ions according to their mass-to-charge ratios. Isomers may share molecular mass, so fragmentation patterns help distinguish them.Structural formula: A representation that shows how atoms are connected in a molecule. It makes the connectivity differences between isomers visible.Functional group isomerism: A form of structural isomerism in which compounds have different functional groups. Rearranged bonds can place the same atoms into different functional groups.Show all 21Linked from 28 pagesIsomerBroader topic: This isomer class differs through its bonding pattern.AlkaneRelated: Alkanes with four or more carbon atoms can have distinct carbon-chain arrangements.RegioselectivityNarrower topic: Regioselective products are constitutional isomers that differ in where groups are attached.Molecular geometryCompared with: Connectivity differences distinguish constitutional isomers before their geometries are compared.IsomerismBroader topic: Structural isomers differ in connectivity, the defining basis of one major branch of isomerism.CycloalkaneRelated: Cycloalkanes can share formulas with alkenes while differing in connectivity.Butyl acetateNarrower topic: Several butyl acetate isomers share a formula while differing in how their atoms are connected.StereochemistryCompared with: Constitutional isomers differ in connectivity, whereas stereoisomers retain the same connectivity.Show all 28