| Terbium - Tb
CAS: 7440-27-9 Description: Silver-gray, malleable, ductile metal. Classification: Rare Earth (Lanthanide) Date of Discovery: 1843 Discoverer: Carl Mosander Name Origin: Ytterby, village in Sweden |
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Atomic Number: 65
Number of Neutrons: 94 Atomic Mass: 158.92534(2) amu Melting Point: 1360.0 °C Boiling Point: 3041.0 °C Density (293 K): 8.27 g/cm3 Atomic volume: 19.30 cm3/mol Electrical resistivity: 120 10-8  m
Thermal conductivity: 0.11 W/cmK Enthalpy of atomization: 314 kJ/mol (est.) Enthalpy of vaporization: 295 kJ/mol Enthalpy of fusion: 10.8 kJ/mol Specific heat capacity: 0.182 J/gK |
Energy levels: 2-8-18-27-8-2
Electron configuration: [Xe]4f96s2 Crystal Structure: Hexagonal Atomic radius: 2.25 Å Covalent radius: 1.61 Å Oxidation States: +3 and +4 Electronegativity, Pauling: 1.2 Electron affinity: First ionization energy: 5.8639 eV 2nd ionization energy: 11.52 eV 3rd ionization energy: 21.91 eV Polarizability: 25.5 10-24cm3 |
| Isotope | Natural Abundance | Atomic Mass | Half-life | Decay Mode | Spin |
| 140Tb | 139.946 | 2.4 s |  +, EC |
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| 141Tb | 140.941 | 3.5 s | +, EC |
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| 142mTb | 0.30 s | +, EC |
4- | ||
| 142Tb | 141.939 | 0.60 s | +, EC |
0+ | |
| 143Tb | 142.9346 | 12 s | +, EC |
11/2- | |
| 144mTb | 4.1 s | IT | 5- | ||
| 144Tb | 143.9324 | < 1.5 s | +, EC |
1+ | |
| 145mTb | 30 s | +, EC |
11/2- | ||
| 145Tb | 144.9287 | +, EC |
1/2+ | ||
| 146mTb | 23 s | +; EC |
(5-) | ||
| 146Tb | 145.9270 |  8 s |
+ |
1+ | |
| 147mTb | 1.8 m | +; EC |
11/2- | ||
| 147Tb | 146.92404 | 1.6 h | +; EC |
5/2+ | |
| 148mTb | 2.3 m | +; EC |
9+ | ||
| 148Tb | 147.92422 | 1.00 h | +, EC |
2- | |
| 149mTb | 4.16 m | EC; + |
11/2- | ||
| 149Tb | 148.923243 | 4.13 h | +;  |
1/2+ | |
| 150mTb | 6.0 m | +; EC |
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| 150Tb | 149.92366 | 3.3 h | +, EC |
2- | |
| 151mTb | 25 s | IT; + |
11/2- | ||
| 151Tb | 150.923099 | 17.61 h | +; EC |
1/2+ | |
| 152mTb | 4.3 m | IT; EC | (8+) | ||
| 152Tb | 151.92407 | 17.5 h | +; EC |
2- | |
| 153Tb | 152.923433 | 2.34 d | EC | 5/2+ | |
| 154m2Tb | 23.1 h | EC; IT | (7-) | ||
| 154m1Tb | 9 h | +; IT |
(3-) | ||
| 154Tb | 153.92469 | 21.5 h | EC; + |
0- | |
| 155Tb | 154.92350 | 5.3 d | EC | 3/2+ | |
| 156m2Tb | 1.02 d | IT | (7-) | ||
| 156m1Tb | 5.3 h | IT | (0+) | ||
| 156Tb | 155.924744 | 5.3 d | EC | 3- | |
| 157Tb | 156.924021 | 110 y | EC | 3/2+ | |
| 158mTb | 10.5 s | IT | 0- | ||
| 158Tb | 157.925410 | 180 y | EC; - |
3- | |
| 159Tb | 100. | 158.925343 | Stable | 3/2+ | |
| 160Tb | 159.927164 | 72.3 d | - |
3- | |
| 161Tb | 160.927566 | 6.91 d | - |
3/2+ | |
| 162Tb | 161.92948 | 7.6 m | - |
(1/2-) | |
| 163Tb | 162.930644 | 19.5 m | - |
3/2+ | |
| 164Tb | 163.9334 | 3.0 m | - |
(5+) | |
| 165Tb | 164.9349 | 2.1 m | - |
3/2+ | |
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Terbium is a member of the lanthanide or "rare earth" group of elements. It is found in cerite, gadolinite, and other minerals along with other rare earths. It is recovered commercially from monazite in which it is present to the extent of 0.03%, from xenotime, and from euxenite, a complex oxide containing 1% of more of terbia. Terbium has been isolated only in recent years with the development of ion-exchange techniques for separating the rare-earth elements. As with other rare earths, it can be produced by reducing the anhydrous chloride or fluoride with calcium metal in a tantalum crucible. Calcium and tantalum impurities can be removed by vacuum remelting. Other methods of isolation are possible. Terbium is reasonably stable in air. It is a silver-gray metal, and is malleable, ductile, and soft enough to be cut with a knife. Two crystal modifications exist, with a transformation temperature of 1289 °C. Forty-one isotopes and isomers are recognized. The oxide is a chocolate or dark maroon color. Sodium terbium borate is used as a laser material and emits coherent light at 0.546 µm. Terbium is used to dope calcium fluoride, calcium tungstate, and strontium molybdate, used in
solid-state devices. The oxide has potential application as an activator for green phosphors used in color TV tubes. It can be used with ZrO2 as a crystal stabilizer of fuel cells which operate at elevated temperature. Few other uses have been found. Little is known of the toxicity of terbium. It should be handled with care as with other lanthanide elements.
LINKS: Alfa Aesar: Terbium foil Information, data sheet and standard forms Photon Interaction Coefficients of Terbium Radiation-induced Luminescence in Terbium-doped Silicate Glasses Reconstruction on Terbium Return
Sources for the information on this website include: Lide, David R., ed. CRC Handbook of Chemistry and Physics, 78th Ed., 1997-1998. |
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