1. 56Bario-BariumMass: 137,327u[Xe] 6s2Melting point: 1000 KBoiling point: 2170 KDensity: 3.51 g/cm3Discovery: Carl Wilhelm Scheele (1772)Barium is a soft, silvery-white metal. It has a medium specific weightand good electrical conductivity. Ultrapure barium is very hard toprepare, and therefore many properties of barium have not beenaccurately measured yet. Barium, as a metal or when alloyed withaluminium, is used to remove unwanted gases (gettering) from vacuumtubes, such as TV picture tubes.