You are a chemist. Now you are given a description of a molecule. Please generate a molecule that meets the description.
system
I give you a description of a molecule, and you need to return one molecule in SMILES that meets the description. The description: The molecule has Mild sulfide. The mustard stimulant, 2-chloroethyl ethyl sulfide decomposes by a mechanism involving formation of dimeric sulfonium ions which transform slowly to 1,4-dithiane as a primary product.
user
CCSCCCl
assistant