Thulium was discovered by Per Theodor Cleve, a Swedish chemist, in 1879.
Name: Thulium
Symbol: Tm
Atomic number: 69
Atomic weight: 168.93
State: solid
Group, period, block: n/a, 6, f
Color: silvery gray
Classification: lanthanide
Electron configuration: 4f13 6s2
2,8,18,31,8,2
Physical properties
Density: 9.32 g/cm-3
Melting point: 1818 K,1545 °C,2813 °F
Boiling point: 2223 K,1950 °C,3542 °F
Atomic properties
Oxidation states: 2, 3, 4
Electronegativity: 1.25 (Pauling scale)
Ionization energies: 1st: 596.7 kJ·mol-1
Covalent radius: 190±10 pm
Van der Waals radius: no data
- Tm
Electron Configuration
Isotopes
There is one naturally occurring isotope of thulium exists, 169Tm.