explosive vs unstable

explosive is a noun but unstable is not a noun.

Word	Noun	Adjective	Verb	Adverb
explosive	Yes	Yes	No	No
unstable	No	Yes	No	No

explosive (noun)	unstable (noun)
a chemical substance that undergoes a rapid chemical change (with the production of gas) on being heated or struck

explosive (adjective)	unstable (adjective)
serving to explode or characterized by explosion or sudden outburst	lacking stability or fixity or firmness
sudden and loud	subject to change; variable
liable to lead to sudden change or violence	suffering from severe mental illness
	disposed to psychological variability
	highly or violently reactive
	affording no ease or reassurance