decrepitation vs decrepitate

decrepitation is a noun but decrepitate is not a noun.

Word	Noun	Adjective	Verb	Adverb
decrepitation	Yes	No	No	No
decrepitate	No	No	Yes	No

decrepitation (noun)	decrepitate (noun)
the crackling or breaking up of certain crystals when they are heated

decrepitation (verb)	decrepitate (verb)
	to roast or calcine so as to cause to crackle or until crackling stops
	undergo decrepitation and crackle