expansive vs expansivity

expansive is not a noun while expansivity is a noun.

Word	Noun	Adjective	Verb	Adverb
expansive	No	Yes	No	No
expansivity	Yes	No	No	No

expansive (noun)	expansivity (noun)
	a friendly open trait of a talkative person
	a quality characterized by magnificence of scale or the tendency to expand
	the fractional change in length or area or volume per unit change in temperature at a given constant pressure

expansive (adjective)	expansivity (adjective)
able or tending to expand or characterized by expansion
friendly and open and willing to talk
marked by exaggerated feelings of euphoria and delusions of grandeur
of behavior that is impressive and ambitious in scale or scope