[{"from": "human", "value": "Design a molecule that meets the criteria outlined in the description. The molecule is a mineral with formula of Cu1+2Fe2+Sn4+S2-4 or Cu2FeSnS4. The corresponding IMA (International Mineralogical Association) number is  . The IMA symbol is Stn."}, {"from": "gpt", "value": "[S].[S].[S].[S].[Fe].[Cu].[Cu].[Sn]"}]