CrO3 + H2SO4; mixture of chromium trioxide and sulphuric acid. Odourless brownish-red liquid. Aggressive etchant for wet chemical etching. Carcinogenic. Causes most severe chemical burns. Risk of loss of eyesight at contact with eyes. Can damage kidneys and liver. Risk of combustion at contact with flammable materials. Must not be heated to high temperatures. Avoid contact with water, alkaline solutions, metals, organic compounds, flammable solvents and flammable materials.