Name: lanthanum
Symbol: La
Atomic number: 57
Atomic weight: 138.9055 (2) g
Group in periodic table:
Group name:
Period in periodic table: 6 (lanthanoid)
Block in periodic table: f-block
CAS registry ID: 7439-91-0
Lanthanum is silvery white, malleable, ductile, and soft enough to be cut with a knife. It 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. It is a component of, misch metal (used for making lighter flints).