inconvertible vs inconvertibility

inconvertible is not a noun while inconvertibility is a noun.

Word	Noun	Adjective	Verb	Adverb
inconvertible	No	Yes	No	No
inconvertibility	Yes	No	No	No

inconvertible (noun)	inconvertibility (noun)
	the quality of not being exchangeable

inconvertible (adjective)	inconvertibility (adjective)
used especially of currencies; incapable of being exchanged for or replaced by another currency of equal value
not capable of being changed into something else