Chromic acid is a hexavalent chromium compound and a powerful oxidizing agent. Hexavalent chromium compound has many different applications; an intermediate in hard chrome plating, anodizing of aluminium, use in ceramic glazes and ceramic glass, and in some cases sealing of phosphate coatings to iron and steel, and bright dipping of brass is still practised. It is also used in the manufacturing of pigments for paint colour. In the past, it was used in the wood preservation industry, as a hexavalent passivate for conversion coating on zinc, as acid cleaning of aluminum and magnesium, and organic synthesis, and for cleaning laboratory glassware and magnetic recording tapes. In many of these applications today there are safer environmental alternatives.