methylene group vs methylene

methylene group and methylene both are nouns.

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

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

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

Other synonyms of methylene group include methylene radical.

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