Date of Discovery: 1839
Discoverer: Carl Mosander
Name Origin: From the Greek word lanthaneis (to lie hidden)
Uses: expensive camera lenses
Obtained From: monazite, bastnasite

 
Atomic Number: 57
Atomic Mass: 138.9055 amu
Melting Point: 920.0 °C (1193.15 °K, 1688.0 °F)
Boiling Point: 3469.0 °C (3742.15 °K, 6276.2 °F)
Crystal Structure: Hexagonal
Density @ 293 K: 6.7 g/cm3
Color: white

 
Isotope
La-134
La-137
La-138
La-139
La-140
La-141
La-142
Half Life
6.5 min
6000.0 years
1.05E10 years
Stable
1.67 days
3.9 hours
1.54 min