unstable vs volatile

unstable is not a noun while volatile is a noun.

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

unstable (noun)	volatile (noun)
	a volatile substance; a substance that changes readily from solid or liquid to a vapor

unstable (adjective)	volatile (adjective)
lacking stability or fixity or firmness	evaporating readily at normal temperatures and pressures
subject to change; variable	tending to vary often or widely
suffering from severe mental illness	marked by erratic changeableness in affections or attachments
disposed to psychological variability	liable to lead to sudden change or violence
highly or violently reactive
affording no ease or reassurance