gravitation vs gravitational

gravitation is a noun but gravitational is not a noun.

Word	Noun	Adjective	Verb	Adverb
gravitation	Yes	No	No	No
gravitational	No	Yes	No	No

gravitation (noun)	gravitational (noun)
a figurative movement toward some attraction
movement downward resulting from gravitational attraction
(physics) the force of attraction between all masses in the universe; especially the attraction of the earth's mass for bodies near its surface

gravitation (adjective)	gravitational (adjective)
	of or relating to or caused by gravitation