Osmium Tetroxide, over 1g (DG)

Osmium Tetroxide, Crystalline, Highest Purity, 99.95%
(Osmic Acid Anhydride)
OsO₄   F.W. 254.20   CAS #20816-12-0
Melting Range : 39.5-41.0°C
Boiling Point : 129.7°C
Vapor Pressure @25°C: 9.8 mmHg
Solubility: 5.07% in Cold Water; 6.5% in Hot Water; 25.0% in CCl₄
Non-Volatile matter: <0.02%

Small size (2 ml), Light-gauge, pre-scored amber glass ampoules. Ampoules containing OsO₄ Crystal, are pre-cleaned and heat sealed in plastic bags to assure a contaminant-free solution. Ampoules are also free of pressure-sensitive labels and, therefore, do not require cleaning prior to solution preparation.

Osmium is a highly toxic, volitile solid, crystalised compound.  It is colourless but almost appears yellow. 

C010 and C012 - Safety Data Sheet