methylene radical vs methylene group

methylene radical and methylene group both are nouns.

Word	Noun	Adjective	Verb	Adverb
methylene radical	Yes	No	No	No
methylene group	Yes	No	No	No

As nouns, methylene radical and methylene group are synonyms defined as:

methylene radical and methylene group: the bivalent radical CH2 derived from methane

Other synonyms of methylene radical include methylene.

methylene radical (noun)	methylene group (noun)
the bivalent radical CH2 derived from methane	the bivalent radical CH2 derived from methane