arsenic vs arsenious

arsenic is a noun but arsenious is not a noun.

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

arsenic (noun)	arsenious (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

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