This is mustard gas; it got its name from the scent, mustard plants.  It was created in mass quantities by the Germans in the early 1900's (around WW1) and is one of my favorite molecules because its formula is simple/symmetric/organic but it is extremely dangerous.  I should also add that I am a fan of history and find the World Wars fascinating because of the advancements in technology, particularly guns and chemical warfare.  Should this compound come in contact with your skin or lungs, it will leave extreme blisters.