United Mexican States vs Ciudad de Mexico

United Mexican States and Ciudad de Mexico both are nouns.

Word	Noun	Adjective	Verb	Adverb
United Mexican States	Yes	No	No	No
Ciudad de Mexico	Yes	No	No	No

United Mexican States (noun)	Ciudad de Mexico (noun)
a republic in southern North America; became independent from Spain in 1810	the capital and largest city of Mexico is a political and cultural and commercial and industrial center; one of the world's largest cities