Description Lanthanum Oxysulfide, 99.5+% (REO), 0.6% Terbium Activated, 100g For Research & Development Not for drug, human, animal, or food use Certificate of Analysis: Appearance (Color) White Appearance (Form) Powder Assay 99.5+% Terbium Activated 0.6% Infrared Spectrum Conforms to structure CAS: 12031-43-5 FORMULA: La2O2S