origin of the name lanthanum
Lanthanum was discovered by Carl Gustaf Mosander in 1839 at Sweden. Origin of name: from the Greek word  lanthanein  meaning  to lie hidden . Carl Gustav Mosander recognized the element lanthanum in impure cerium nitrate in 1839.t is one of the most reactive of the rare-earth metals. It oxidises rapidly when exposed to air. Cold water attacks lanthanum slowly, and hot water attacks it much more rapidly. The metal reacts directly with elemental carbon, nitrogen, boron, selenium, silicon, phosphorus, sulphur, and with halogens.