 For example, effluent from such refineries is treated with reducing agents to return any chromium(VI) to chromium(III), which is less threatening to the environment.A variety of hydrates of this salt are known, ranging from the decahydrate below 19.5 °C (CAS# ) as well as hexa-, tetra-, and dihydrates.Above 62 °C, these salts lose water spontaneously to give the anhydrous material.