69Solid
Tm 168.934 Atomic mass · uLanthanides
Thulium
Thulium is a chemical element with symbol Tm and atomic number 69. It is the thirteenth and antepenultimate (third-last) element in the lanthanide series. Like the other lanthanides, the most common oxidation state is +3, seen in its oxide, halides and other compounds.
Discovery 1879 (Per Teodor Cleve)
K2L8M18N31O8P2
Physical properties
Values for the element in its standard state.
- Density
- 9.321g/cm³
- Melting point
- 1,818K
- Boiling point
- 2,223K
- Atomic radius
- Not available
- Bonding type
- Metallic
- Molar heat
- 27.03J/(mol·K)
Inside the atom
Electron arrangement and the energy behind its behavior.
Full electron configuration
1s, 2 electrons; 2s, 2 electrons; 2p, 6 electrons; 3s, 2 electrons; 3p, 6 electrons; 3d, 10 electrons; 4s, 2 electrons; 4p, 6 electrons; 4d, 10 electrons; 5s, 2 electrons; 5p, 6 electrons; 4f, 13 electrons; 6s, 2 electrons;
[Xe] represents 54 core electrons. The full view shows them explicitly.
69 electrons Orbital order preserved from source
- Electronegativity
- 1.25Pauling scale
- First ionization energy
- 597kJ/mol
- Electron affinity
- 50kJ/mol
- Van der Waals radius
- Not available
Tm ThuliumAtomic number 69
597kJ/mol
Atomic numberGaps indicate unavailable data
About thulium
- Appearance
- Silvery gray
- Discovery
- 1879 (Per Teodor Cleve)
- Data source
- Read the reference
A missing value means it is unavailable in this reference dataset. Values can vary with measurement method and conditions.