Samarium sulfide is yellowish-brown crystal powder, which is rare earth metal sulfide. It is stable at room temperature and pressure. When heating above 200â??, Sm2S3 oxidize. Samarium(III) sulfide can oxidize to oxide by hydrogen perxoide and other oxidizing agent. Samarium trisulfide decompose in hot water and dilute acid. Samarium(III) oxide is the raw material. Samarium Sulfide Sm/RES=99% CAS No.:12067-22-0 EC No.:235-076-6 Molecular Formula:Sm2S3 Molecular Weight:396.89 Density:5.729 Melting Point:1900 -