Ferric chloride is an orange to brown-black solid. It is slightly soluble in water. It is noncombustible. When wet it is corrosive to aluminum and most metals. Pick up and remove spilled solid before adding water. It is used to treat sewage, industrial waste, to purify water, as an etching agent for engraving circuit boards, and in the manufacture of other chemicals. Ferric chloride, solution appears as a colorless to light brown aqueous solution that has a faint hydrochloric acid odor. Highly corrosive to most metals and probably corrosive to tissue. Noncombustible. Used in sewage treatment and water purification.