Information valid for La-139 unless otherwise noted

Lanthanum

Basic Information

Symbol: La
Atomic Number: 57
Mass: 138.9055
Melting Point: 920.0 C
Boiling Point: 3469.0 C
Number of Protons/Electrons: 57
Number of Neutrons: 82
Classification: Rare Earth
Crystal Structure: Hexagonal
Density @ 293 K: 6.7 g/cm³
Color: white

Atomic Structure

Number of Energy Levels: 6 First Energy Level: 2 Second Energy Level: 8 Third Energy Level: 18 Fourth Energy Level: 18 Fifth Energy Level: 9 Sixth Energy Level: 2

Isotopes

Facts

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