capital of Finland vs national capital

capital of Finland and national capital both are nouns.

Word	Noun	Adjective	Verb	Adverb
capital of Finland	Yes	No	No	No
national capital	Yes	No	No	No

capital of Finland (noun)	national capital (noun)
the capital and largest city of Finland; located in southern Finland; a major port and commercial and cultural center	the capital city of a nation