As an adjective isomeric
is (chemistry|physics) being an isomer.
As a noun tridecane is
tridecane.
isomeric
English
Adjective
(-)
(chemistry, physics) Being an isomer.
(chemistry) Exhibiting isomerism.
tridecane
English
Noun
(
en noun)
(organic compound) Any of very many isomeric saturated aliphatic hydrocarbons having thirteen carbon atoms, but especially n-tridecane , CH3(CH2)11CH3