valency vs valent

valency is a noun but valent is not a noun.

Word	Noun	Adjective	Verb	Adverb
valency	Yes	No	No	No
valent	No	Yes	No	No

valency (noun)	valent (noun)
(chemistry) a property of atoms or radicals; their combining power given in terms of the number of hydrogen atoms (or the equivalent)
(biology) a relative capacity to unite or react or interact as with antigens or a biological substrate
the phenomenon of forming chemical bonds

valency (adjective)	valent (adjective)
	(chemistry) having valence; usually used in combination