sulfurous vs sulfur

sulfurous is not a noun while sulfur is a noun.

Word	Noun	Adjective	Verb	Adverb
sulfurous	No	Yes	No	No
sulfur	Yes	No	Yes	No

sulfurous (noun)	sulfur (noun)
	an abundant tasteless odorless multivalent nonmetallic element; best known in yellow crystals; occurs in many sulphide and sulphate minerals and even in native form (especially in volcanic regions)

sulfurous (adjective)	sulfur (adjective)
of or related to or containing sulfur or derived from sulfur
characterized by oppressive heat and humidity
harsh or corrosive in tone

sulfurous (verb)	sulfur (verb)
	treat with sulphur in order to preserve