69
168.93
Tm
Thulium
Identification
CAS Number: 7440-30-4
Discovery Year: 1879
Discoverer: Per Theodor Cleve
Discovery Location: Sweden
Properties
Atomic Dimensions
Atomic Radius: 175 pm →
Atomic Radius (Rahm): 271 pm
Covalent Radius: 190 pm →Van der Waals Radius: 227 pm
Atomic Volume: 18.1 cm³/mol
Lattice Constant: 3.54 Å
Thermodynamics
Melting Point: 1818 K →Boiling Point: 2220 K →Specific Heat: 0.16 J/(g·K) →Heat of Vaporization: 232 kJ/mol →
Heat of Formation: 232.2 kJ/mol
Electronic Structure
Electron Config: [Xe] 4f13 6s2
Block: f
Period: 6 →Electronegativity: 1.25 →Electron Affinity: 1.0290000000000001 eV →Oxidation States: +2, +3
Abundance & Geochemistry
Crust Abundance: 0.52 mg/kg
Sea Abundance: 1.7e-7 mg/L
Geochemical Class: rare earth & related
Goldschmidt Class: litophile
About
Soft grey metallic element that belongs to the lanthanoids. One natural isotope exists, Tm-169, and seventeen artificial isotopes have been produced. No known uses for the element. Discovered in 1879 by Per Theodor Cleve.
Isotopes
Tm-169 169 100.00%