multivalent vs valency

multivalent is not a noun while valency is a noun.

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

multivalent (noun)	valency (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

multivalent (adjective)	valency (adjective)
used of the association of three or more homologous chromosomes during the first division of meiosis
having more than one valence, or having a valence of 3 or higher
having many values, meanings, or appeals