Isomerism
Two molecules are isomers if 1) they are not identical or conformers 2) they have the same molecular formula
Constitutional isomerism
Two molecules are isomers of constitution if 1) they are isomers 2) they have a different semi-developed formula
Chain isomerism: Different branching of the hydrocarbon chain:
Positional isomerism: Different position of chemical functional group:
Functional isomerism: Different chemical functional group:
Configurational isomerism
Two molecules are configurational isomers if 1) they are isomers 2) they have the same semi-developed formula
Cis-trans isomerism: Rigidity of the double bond C=C or cycle:
Enantiomerism: C atom with 4 different substituents (asymmetric C )
Same substance or non?
Two isomers can be separated at normal temperature.
Two isomer molecules do not belong to the same chemical substance.