arsenious vs arsenic

arsenious is not a noun while arsenic is a noun.

Word	Noun	Adjective	Verb	Adverb
arsenious	No	Yes	No	No
arsenic	Yes	No	No	No

arsenious (noun)	arsenic (noun)
	a very poisonous metallic element that has three allotropic forms; arsenic and arsenic compounds are used as herbicides and insecticides and in various alloys; found in arsenopyrite and orpiment and realgar
	a white powdered poisonous trioxide of arsenic; used in manufacturing glass and as a pesticide (rat poison) and weed killer

arsenious (adjective)	arsenic (adjective)
relating to compounds in which arsenic is trivalent