Terbium (Tb)
lanthanideSolid
Standard Atomic Weight
158.92535 uElectron configuration
[Xe] 6s2 4f9Melting point
1355.85 °C (1629 K)Boiling point
3229.85 °C (3503 K)Density
8230 kg/m³Oxidation states
0, +1, +2, +3, +4Electronegativity (Pauling)
N/AIonization energy (1st)
Discovery year
1843Atomic radius
175 pmDetails
Terbium is a lanthanide rare-earth metal with atomic number 65. It is chemically similar to neighboring gadolinium and dysprosium and occurs in minerals with other rare earths rather than as a native element. Its most distinctive technological role comes from Tb³⁺ luminescence, which gives intense green emission in suitable host materials, and from the large magnetostrictive response of terbium-containing alloys.
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. Twenty one isotopes with atomic masses ranging from 145 to 165 are recognized. The oxide is a chocolate or dark maroon color.
The name derives from the village of Ytterby in Sweden, where the mineral ytterbite (the source of terbium) was first found. Terbium was discovered by the Swedish surgeon and chemist Carl-Gustav Mosander in 1843 in an yttrium salt, which he resolved into three elements. He called one yttrium, a rose-colored salt he called terbium, and a deep-yellow peroxide he called erbium. In 1862, the Swiss chemist Marc Delafontaine reexamined yttrium and found the yellow peroxide. Because the name erbium had now been assigned to the rose-colored oxide, he reintroduced the name terbium for the yellow peroxide. Thus the original names given to erbium and terbium samples are now switched.
The mineral gadolinite ((Ce, La, Nd, Y)2FeBe2Si2O10), discovered in a quarry near the town of Ytterby, Sweden, has been the source of a great number of rare earth elements. In 1843, Carl Gustaf Mosander, a Swedish chemist, was able to separate gadolinite into three materials, which he named yttria, erbia and terbia. As might be expected considering the similarities between their names and properties, scientists soon confused erbia and terbia and, by 1877, had reversed their names. What Mosander called erbia is now called terbia and visa versa. From these two substances, Mosander discovered two new elements, terbium and erbium. Today, terbium can be obtained from the minerals xenotime (YPO4) and euxenite ((Y, Ca, Er, La, Ce, U, Th)(Nb, Ta, Ti)2O6), but is primarily obtained through an ion exchange process from monazite sand ((Ce, La, Th, Nd, Y)PO4), a material rich in rare earth elements that typically contains as much as 0.03% terbium.
Discovered by Mosander in 1843. 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% or more of terbia.
Images
Properties
Physical
Chemical
Thermodynamic
Nuclear
Abundance
Reactivity
N/A
Crystal Structure
Electronic Structure
Identifiers
Electron Configuration Measured
Tb: 4f⁹ 6s²[Xe] 4f⁹ 6s²1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f⁹ 6s²Atomic model
Isotopes change neutron count, mass, and stability — not the electron configuration of a neutral atom.
Schematic atomic model, not to scale.
Atomic Fingerprint
Emission / Absorption Spectrum
Isotope Distribution
| Mass number | Atomic mass (u) | Natural abundance | Half-life |
|---|---|---|---|
| 159 Stable | 158.9253547 ± 0.0000019 | 100.0000% | Stable |
Phase / State
Reason: 1330.8 °C below melting point (1355.85 °C)
Schematic, not to scale
Phase transition points
Transition energies
Energy required to melt 1 mol at melting point
Energy required to vaporize 1 mol at boiling point
Energy required to sublime 1 mol at sublimation point
Density
At standard conditions
At standard conditions
Atomic Spectra
Showing 10 of 65 Atomic Spectra. Sorted by ion charge (ascending).
Lines Holdings ?
| Ion | Charge | Total lines | Transition probabilities | Level designations |
|---|---|---|---|---|
| Tb I | 0 | 248 | 0 | 10 |
| Tb II | +1 | 424 | 8 | 18 |
| Tb IV | +3 | 48 | 0 | 0 |
Levels Holdings ?
| Ion | Charge | Levels |
|---|---|---|
| Tb I | 0 | 600 |
| Tb II | +1 | 154 |
| Tb III | +2 | 125 |
| Tb IV | +3 | 26 |
| Tb V | +4 | 2 |
| Tb VI | +5 | 2 |
| Tb VII | +6 | 2 |
| Tb VIII | +7 | 2 |
| Tb IX | +8 | 2 |
| Tb X | +9 | 2 |
Ionic Radii
| Charge | Coordination | Spin | Radius |
|---|---|---|---|
| +3 | 6 | N/A | 92.30000000000001 pm |
| +3 | 7 | N/A | 98 pm |
| +3 | 8 | N/A | 104 pm |
| +3 | 9 | N/A | 109.5 pm |
| +4 | 6 | N/A | 76 pm |
| +4 | 8 | N/A | 88 pm |
Compounds
Isotopes (1)
| Mass number | Atomic mass (u) | Natural abundance | Half-life | Decay mode | |
|---|---|---|---|---|---|
| 159 Stable | 158.9253547 ± 0.0000019 | 100.0000% | Stable | stable |
Extended Properties
Covalent Radii (Extended)
Van der Waals Radii
Atomic & Metallic Radii
Numbering Scales
Electronegativity Scales
Polarizability & Dispersion
Miedema Parameters
Supply Risk & Economics
Phase Transitions & Allotropes
| Melting point | 1632.15 K |
| Boiling point | 3503.15 K |
Oxidation State Categories
Advanced Reference Data
Screening Constants (13)
| n | Orbital | σ |
|---|---|---|
| 1 | s | 1.2739 |
| 2 | p | 4.3076 |
| 2 | s | 17.0278 |
| 3 | d | 13.7015 |
| 3 | p | 19.9853 |
| 3 | s | 20.4485 |
| 4 | d | 34.69 |
| 4 | f | 39.1352 |
| 4 | p | 31.6012 |
| 4 | s | 30.98 |
Crystal Radii Detail (6)
| Charge | CN | Spin | rcrystal (pm) | Origin |
|---|---|---|---|---|
| 3 | VI | 106.3 | from r^3 vs V plots, | |
| 3 | VII | 112 | estimated, | |
| 3 | VIII | 118 | from r^3 vs V plots, | |
| 3 | IX | 123.5 | from r^3 vs V plots, | |
| 4 | VI | 90 | from r^3 vs V plots, | |
| 4 | VIII | 102 |
Isotope Decay Modes (63)
| Isotope | Mode | Intensity |
|---|---|---|
| 135 | p | 100% |
| 135 | B+ | — |
| 136 | B+ | — |
| 136 | B+p | — |
| 137 | p | — |
| 137 | B+ | — |
| 138 | B+ | — |
| 138 | B+p | — |
| 138 | p | 0% |
| 139 | B+ | 100% |
X‑ray Scattering Factors (514)
| Energy (eV) | f₁ | f₂ |
|---|---|---|
| 10 | — | 0.15974 |
| 10.1617 | — | 0.16625 |
| 10.3261 | — | 0.17301 |
| 10.4931 | — | 0.18005 |
| 10.6628 | — | 0.18738 |
| 10.8353 | — | 0.19501 |
| 11.0106 | — | 0.20295 |
| 11.1886 | — | 0.21121 |
| 11.3696 | — | 0.21981 |
| 11.5535 | — | 0.22823 |
Additional Data
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
1.2 milligrams per kilogram
References (1)
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
1.4×10-7 milligrams per liter
References (1)
Production
Production of this element (from raw materials or other compounds containing the element).
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 earth metals, 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.
References (1)
- [6] Terbium https://periodic.lanl.gov/65.shtml
References
(9)
Data deposited in or computed by PubChem
The half-life and atomic mass data was provided by the Atomic Mass Data Center at the International Atomic Energy Agency.
Element data are cited from the Atomic weights of the elements (an IUPAC Technical Report). The IUPAC periodic table of elements can be found at https://iupac.org/what-we-do/periodic-table-of-elements/. Additional information can be found within IUPAC publication doi:10.1515/pac-2015-0703 Copyright © 2020 International Union of Pure and Applied Chemistry.
The information are cited from Pure Appl. Chem. 2018; 90(12): 1833-2092, https://doi.org/10.1515/pac-2015-0703.
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The periodic table at the LANL (Los Alamos National Laboratory) contains basic element information together with the history, source, properties, use, handling and more. The provenance data may be found from the link under the source name.
The periodic table contains NIST's critically-evaluated data on atomic properties of the elements. The provenance data that include data for atomic spectroscopy, X-ray and gamma ray, radiation dosimetry, nuclear physics, and condensed matter physics may be found from the link under the source name. Ref: https://www.nist.gov/pml/atomic-spectra-database
This section provides all form of data related to element Terbium.
The element property data was retrieved from publications.