Terbium is a chemical element with the symbol Tb and atomic number 65.
Terbium is a silvery-white rare earth metal that is malleable, ductile and soft enough to be cut with a knife. It is reasonably stable in air, and two crystal allotropes exist, with a transformation temperature of 1289 °C. Terbium(III) cation is brilliantly fluorescent, in a beautiful bright lemon-yellow color that is the result of a strong green emission line in combination with other lines in the orange and red. The yttrofluorite variety of the mineral fluorite owes its creamy-yellow fluorescence in part to terbium.
| Technical Data | ||||||||
| Symbol | Tb | Melting point / C | 1356 | |||||
| Atomic number | 65 | Boiling point / °C | -2800 | |||||
| No. of naturally occurring isotopes | 1 | ΔHvap/kJmol-1 | 293 | |||||
| Atomic weight | 158.9254 | ΔHf(monoatomic gas)/kJmol-1 | 389 | |||||
| Outer electron configuration | 4f962 | ΔH(hydration Ln3+)/kJmol-1 | 3605 | |||||
| Metal radius(6-coordinate)/pm | 177.3 | Electrical resistivity | ||||||
| Ionic radius(6-coordinate)/pm IV | 76 | (25°C)/μohm cm | 116 | |||||
| Ionic radius(6-coordinate)/pm III | 92.3 | Ionization energy/kJmol-1 I | 569 | |||||
| E° (M4+(aq)\ + e- →M3+(aq))/V | 2.7 | Ionization energy/kJmol-1 II | 1112 | |||||
| E° (M3+(aq)\ + 3e- →M(s))/V | -2.391 | Ionization energy/kJmol-1 III | 2122 | |||||
| Density (25 C)/gcm | 8.253 | |||||||
| Evaporation Techniques | ||||||||
| Temperature (oC) @Vap. Pressure | Techniques | Remarks | ||||||
| 10-8 Torr | 10-6 Torr | 10-4 Torr | Electron Beam | Crucible | Coil | Boat | ||
| 800 | 950 | 1150 | Excellent | Al2O3 | - | Tantalum | Go to Evaporation Sources Page | |