Symbol: Tm
Atomic Number: 69
Atomic Weight: 168.93421
Element Classification: Rare Earth Element (Lanthanide Series)
Discovered By: Per Theodor Cleve
Discovery Date: 1879 (Sweden)
Name Origin: Thule, ancient name of Scandinavia.
Density (g/cc): 9.321
Melting Point (K): 1818
Boiling Point (K): 2220
Appearance: Soft, malleable, ductile, silvery metal
Atomic Radius (pm): 177
Atomic Volume (cc/mol): 18.1
Covalent Radius (pm): 156
Ionic Radius: 87 (+3e)
Specific Heat (@20°C J/g mol): 0.160
Fusion Heat (kJ/mol): n/a
Evaporation Heat (kJ/mol): 232
Thermal Conductivity (@25°C W/m K):
Debye Temperature (K): n/a
Pauling Negativity Number: 1.25
First Ionizing Energy (kJ/mol): 589
Oxidation States: 3, 2
Electronic Configuration: [Xe] 4f¹³ 6s²
Lattice Structure: Hexagonal (HEX)
Lattice Constant (Å): 3.540
Lattice C/A Ratio: 1.570