chelation vs chemical action

chelation and chemical action both are nouns.

Word	Noun	Adjective	Verb	Adverb
chelation	Yes	No	No	No
chemical action	Yes	No	No	No

As nouns, chemical action is a hypernym of chelation; that is, chemical action is a word with a broader meaning than chelation:

chelation: the process of forming a ring by forming one or more hydrogen bonds
chemical action: (chemistry) any process determined by the atomic and molecular composition and structure of the substances involved

Other hypernyms of chelation include chemical change, chemical process.

chelation (noun)	chemical action (noun)
the process of forming a ring by forming one or more hydrogen bonds	(chemistry) any process determined by the atomic and molecular composition and structure of the substances involved
(medicine) the process of removing a heavy metal from the bloodstream by means of a chelate as in treating lead or mercury poisoning