Osmium tetraoxide solution

Osmium tetraoxide solution 4 %, for electron microscopy, Molar mass (M) 254,20 g/mol, Density (D) 1,01 g/cm³, Boiling point (bp) 100 °C, Storage temp. +4 to +15 °C, CAS No. [20816-12-0], UN-Nr. 3287, EG-Nr. 244-058-7, Empirical formula OsO4