Symbol: La
Atomic Number: 57
Atomic Weight: 138.9055
Element Classification: Rare Earth Element (Lanthanide Series)
Discovered By: Carl Mosander
Discovery Date: 1839 (Sweden)
Name Origin: Greek: lanthanein (to be hidden).
Density (g/cc): 6.15
Melting Point (K): 1194
Boiling Point (K): 3730
Appearance: Silvery-white, soft, malleable, and ductile metal
Atomic Radius (pm): 187
Atomic Volume (cc/mol): 22.5
Covalent Radius (pm): 169
Ionic Radius: 101.6 (+3e)
Specific Heat (@20°C J/g mol): 0.197
Fusion Heat (kJ/mol): 8.5
Evaporation Heat (kJ/mol): 402
Thermal Conductivity (@25°C W/m K):
Debye Temperature (K): 132.00
Pauling Negativity Number: 1.10
First Ionizing Energy (kJ/mol): 541.1
Oxidation States: 3
Electronic Configuration: [Xe] 5d¹ 6s²
Lattice Structure: Hexagonal (HEX)
Lattice Constant (Å): 3.750
Lattice C/A Ratio: 1.619