arsenic trioxide vs arsenous anhydride

arsenic trioxide and arsenous anhydride both are nouns.

Word	Noun	Adjective	Verb	Adverb
arsenic trioxide	Yes	No	No	No
arsenous anhydride	Yes	No	No	No

As nouns, arsenic trioxide and arsenous anhydride are synonyms defined as:

arsenic trioxide and arsenous anhydride: a white powdered poisonous trioxide of arsenic; used in manufacturing glass and as a pesticide (rat poison) and weed killer

Other synonyms of arsenic trioxide include arsenic, arsenous oxide, ratsbane, white arsenic.

arsenic trioxide (noun)	arsenous anhydride (noun)
a white powdered poisonous trioxide of arsenic; used in manufacturing glass and as a pesticide (rat poison) and weed killer	a white powdered poisonous trioxide of arsenic; used in manufacturing glass and as a pesticide (rat poison) and weed killer