covalency vs covalence

covalency and covalence both are nouns.

Word	Noun	Adjective	Verb	Adverb
covalency	Yes	No	No	No
covalence	Yes	No	No	No

As nouns, covalency and covalence are synonyms defined as:

covalency and covalence: valence characterized by the sharing of electrons in a chemical compound; the number of pairs of electrons an atom can share

covalency (noun)	covalence (noun)
valence characterized by the sharing of electrons in a chemical compound; the number of pairs of electrons an atom can share	valence characterized by the sharing of electrons in a chemical compound; the number of pairs of electrons an atom can share