CAS: 1317-37-9 Molecular Formula: FeS Molecular Weight: 87.91 g/mol Synonym(s): Ferrous sulfide Test Result Description Dark brown powder and/or chunks X-Ray Diffraction Conforms to standard pattern ICP Assay Confirms Fe and S components Assay (Titration) 61.6 - 65.4% Fe (with sodium thiosulfate) Assay (Metals Basis) 99.8% Total Metallic Impurities