volatile vs unstable

volatile is a noun but unstable is not a noun.

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

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

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