ALKALINE EARTH METALBarium was discovered by Sir Humphry Davy (GB) in 1808.Theoriginofthe name comes from the Greekwordbarysmeaningheavy. It is a soft,slightlymalleable,silvery-whitemetal. Barium oxidises in air andreactswith water.Solublecompounds are toxic by ingestion. Barium isfoundinbarytine(BaSO4) and witherite (BaCO3), it is never foundinpureform dueto its reactivity. Barium must be stored underkerosenetoremainpure. Barite, or barium sulfate (BaSO4) is used asafilterforrubber, plastics and resins. It is insoluble in waterandsoisused in X-rays of the digestive system.Bariumnitrate,Ba(NO3)2,burns brilliant green and is usedinfireworks.