Osmium tetraoxide, min. 99,95 %, p.a. for electron microscopy, Molar mass (M) 254,20 g/mol, Density (D) 4,9 g/cm³, Boiling point (bp) 130 °C, Storage temp. +4 to +15 °C, CAS No. [20816-12-0], UN-Nr. 2471, EG-Nr. 244-058-7, Empirical formula OsO4