Thulium (Tm) — Element 69: Properties & Data | Aladdin Scientific
Thulium(Tm) — Element 69
Thulium (Tm) is a lanthanide with atomic number 69 and atomic mass 168.934. It has melting point 1818 K (1545 °C), boiling point 2223 K (1950 °C), density 9.32 g/cm³. It sits in period 6 of the periodic table and was discovered in 1879.
Key facts
| Atomic mass | 168.9342 u |
|---|---|
| Electron configuration | [Xe]6s2 4f13 |
| Oxidation states | +3 |
| Electronegativity (Pauling) | 1.25 |
| Atomic radius (van der Waals) | 227 pm |
| Ionization energy | 6.184 eV |
| Melting point | 1818 K |
| Boiling point | 2223 K |
| Density | 9.32 g/cm³ |
| Standard state | Solid |
| Year discovered | 1879 |
Frequently asked questions
What is the electron configuration of thulium?
The ground-state electron configuration of thulium is [Xe]6s2 4f13.
What group and period is thulium in?
Thulium (Tm) is in period 6 (lanthanide series) of the periodic table, classified as a lanthanide.
What is the melting point of thulium?
Thulium melts at 1818 K (1545 °C).
What is the standard state of thulium?
Thulium is a solid at standard temperature and pressure.
Related elements
About this data: property values compiled from IUPAC Standard Atomic Weights (2021), the NIST Atomic Spectra Database, and PubChem. Curated by the Aladdin Scientific technical team. Last reviewed: .