sulfur mustard vs mustard gas

sulfur mustard and mustard gas both are nouns.

Word	Noun	Adjective	Verb	Adverb
sulfur mustard	Yes	No	No	No
mustard gas	Yes	No	No	No

As nouns, sulfur mustard and mustard gas are synonyms defined as:

sulfur mustard and mustard gas: a toxic war gas with sulfide based compounds that raises blisters and attacks the eyes and lungs; there is no known antidote

Other synonyms of sulfur mustard include blistering agent, dichloroethyl sulfide, mustard agent.

sulfur mustard (noun)	mustard gas (noun)
a toxic war gas with sulfide based compounds that raises blisters and attacks the eyes and lungs; there is no known antidote	a toxic war gas with sulfide based compounds that raises blisters and attacks the eyes and lungs; there is no known antidote