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Terbium

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Terbium

Atomic Mass	158.92535
Electron Configuration	[Xe]6s24f9
Oxidation States	+3
Year Discovered	1843

Terbium

Atomic Mass	158.92535
Electron Configuration	[Xe]6s24f9
Oxidation States	+3
Year Discovered	1843

Identifiers

Element Name	Terbium
Element Symbol	Tb
InChI	InChI=1S/Tb
InChIKey	GZCRRIHWUXGPOV-UHFFFAOYSA-N

Properties

Atomic Weight	158.925 354(7) 158.92535 158.9 158.92535(2)
Electron Configuration	[Xe]6s²4f⁹
Atomic Radius	Van der Waals Atomic Radius :221 pm (Van der Waals) Empirical Atomic Radius :175pm (Empirical) Covalent Atomic Radius :194(5) pm (Covalent)
Oxidation States	+3 4, 3, 2, 1 (a weakly basic oxide)
Ground Level	⁶H°_15/2
Ionization Energy	5.864 eV 5.8638 ± 0.0006 eV
Atomic Spectra	Lines Holdings Levels Holdings
Physical Description	Solid
Element Classification	Metal
Element Period Number	6
Element Group Number	- Lanthanide
Density	8.23 grams per cubic centimeter
Melting Point	1629 K (1356°C or 2473°F) 1356°C
Boiling Point	3503 K (3230°C or 5846°F) 3123°C
Estimated Crustal Abundance	1.2 milligrams per kilogram
Estimated Oceanic Abundance	1.4×10^-7 milligrams per liter

History

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.

Historical Atomic Weights

Year	Atomic Weight (uncertainty) [u]	Reference
2021	158.925 354(7)	https://doi.org/10.1515/pac-2019-0603
2017	158.925 354(8)	https://doi.org/10.1515/pac-2019-0603
2005	158.925 35(2)	https://doi.org/10.1351/pac200678112051
1995	158.925 34(2)	https://doi.org/10.1351/pac199668122339
1985	158.925 34(3)	https://doi.org/10.1351/pac198658121677
1969	158.9254(1)	https://doi.org/10.1351/pac197021010091
1961	158.924	https://doi.org/10.1021/ja00881a001
1953	158.93	https://doi.org/10.1039/JR9540004713
1907	159.2	https://doi.org/10.1021/ja01956a001
1902	160	https://doi.org/10.1007/BF01370337

Historical Isotopic Abundances

Year	Isotope	Abundance (uncertainty)	Reference
1975, ¹⁵⁹Tb, 1, doi:10.1351/pac197647010075

Description

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.

Users

Terbium is used to dope some types of solid-state devices and, along with zirconium dioxide (ZrO2), as a crystal stabilizer in fuel cells that operate at high temperatures.

Terbia, the renamed material that Mosander discovered in 1843, is terbium oxide (Tb2O3), one of terbium's compounds. Terbia can potentially be used as an activator for green phosphors in television tubes. Sodium terbium borate, another terbium compound, is used to make laser light.

Sodium terbium borate is used in solid-state devices. It can be used with ZrO2 as a crystal stabilizer of fuel cells which operate at elevated temperature. Few other uses have been found.

Compounds

See more information at the Terbium compound page.

Element Forms

CID	Name	Formula	SMILES	Molecular Weight
23958	terbium	Tb	[Tb]	158.92535
168051	terbium(3+)	Tb+3	[Tb+3]	158.92535
161008	terbium-160	Tb	[160Tb]	159.92717
177424	terbium-155	Tb	[155Tb]	154.9235
177425	terbium-157	Tb	[157Tb]	156.92403
177426	terbium-161	Tb	[161Tb]	160.92758
177555	terbium-149	Tb	[149Tb]	148.92325
177556	terbium-150	Tb	[150Tb]	149.92366
177540	terbium-151	Tb	[151Tb]	150.92311
177423	terbium-156	Tb	[156Tb]	155.92475
177531	terbium-153	Tb	[153Tb]	152.92344
167407	terbium-154	Tb	[154Tb]	153.9247
167413	terbium-158	Tb	[158Tb]	157.92542
176433	terbium-147	Tb	[147Tb]	146.92405
11412531	terbium(4+)	Tb+4	[Tb+4]	158.92535
10125068	terbium-148	Tb	[148Tb]	147.9243
10192580	terbium-152	Tb	[152Tb]	151.9241
10241145	terbium-166	Tb	[166Tb]	165.93794
46898733	terbium-161(3+)	Tb+3	[161Tb+3]	160.92758

Handling And Storage

Little is known of the toxicity of terbium. It should be handled with care as with other lanthanide element

Isotopes

Stable Isotope Count	1

Isotopes in Medicine

149Tb (with a half-life of 4.1 h) is being used in targeted radiotherapy using alpha particles for labeling radioimmunoconjugates in cancer treatments [458], [459]. 161Tb (with a half-life of 6.9 days) attached to a bioconjugate (two covalently linked molecules, one or more of which is a biomolecule), is being used in cancer therapy as a targeted radiation treatment of cancer cells [459], [460]. 161Tb is being used for imaging as it allows for on-line monitoring of its distribution using gamma cameras [460]. 149Tb is produced by the reaction 142Nd(12C,5n) 149Dy, which is followed by a subsequent positron decay reaction 149Dy→ 149Tb+β +. It can also be produced by the reaction 141Pr(12C,4n) 149Tb; beam geometry is important for satisfactory yield of 149Tb (Fig. IUPAC.65.1) [461].

Fig. IUPAC.65.1: ¹⁴⁹Tb is produced from the reaction ¹⁴²Nd(¹²C,5n) ¹⁴⁹Dy, which is followed by a subsequent positron decay reaction ¹⁴⁹Dy → ¹⁴⁹Tb + β ⁺. A ten-fold increase in production is achieved by optimal beam geometry (modified from [461]).

[458] N. G. Zaitseva, S. N. Dmitriev, O. D. Maslov, L. G. Molokanova, G. Y. Starodub, S. V. Shishkin, T. V. Shishkina, G. J. Beyer. Czech. J. Phys. Suppl.53, A455 (2003).

[459] G. J. Beyer, M. Miederer, S. Vranjes-Duric, J. J. Comor, G. Kunzi, O. Hartley, R. Senekowitsch-Schmidtke, D. Soloviev, F. Buchegger. Eur. J. Nucl. Med. Mol. Imaging31, 547 (2004).

[460] S. Lehenberger, C. Barkhausen, S. Cohrs, E. Fischer, J. Grünberg, A. Hohn, U. Köster, R. Schibli, A. Türler, K. Zhernosekov. Nucl. Med. Biol.38, 917 (2011).

[461] S. Sarkar, B. J. Allen, S. Imam, G. Goozee, J. Leigh, H. Meriaty. “Production and separation of terbium-149,152 for targeted cancer therapy”, in Second international conference on isotopes; Sydney, NSW (Australia); 273 p. Conference proceedings, 12–16 Oct 1997, C. J. Hardy (Ed.), Australian Nuclear Association Inc., Sutherland, NSW (Australia), pp. 206–211.

Isotope Mass and Abundance

Isotope	Atomic Mass (uncertainty) [u]	Abundance (uncertainty)
^159Tb	158.925 354(7)	1

Isotope	Atomic Mass (uncertainty) [u]	Abundance (uncertainty)
¹⁵⁹Tb	158.9253547(19)	1

Atomic Mass, Half Life, and Decay

Nuclide	Atomic Mass and Uncertainty [u]	Half Life and Uncertainty	Discovery Year	Decay Modes, Intensities and Uncertainties [%]
¹³⁵Tb	134.964516 ± 0.000429 [Estimated]	1.01 ms ± 0.28	2004	p≈100%; β⁺ ?
¹³⁶Tb	135.961460 ± 0.000537 [Estimated]	200 ms [Estimated]		β⁺ ?; β⁺p ?
¹³⁷Tb	136.956020 ± 0.00043 [Estimated]	600 ms [Estimated]		p ?; β⁺ ?
¹³⁸Tb	137.953193 ± 0.000322 [Estimated]	800 ms >200ns [Estimated]	1993	β⁺ ?; β⁺p ?; p=0%
¹³⁹Tb	138.948330 ± 0.00032 [Estimated]	1.6 s ± 0.2	1999	β⁺=100%; β⁺p ?
¹⁴⁰Tb	139.945805048 ± 0.000859359	2.29 s ± 0.15	1986	β⁺=100%; ε<3%; β⁺p=0.26±1.3%
¹⁴¹Tb	140.941448000 ± 0.000113	3.5 s ± 0.2	1986	β⁺=100%
¹⁴¹Tb^m	140.941448000 ± 0.000113	7.9 s ± 0.6	1988	β⁺=100%
¹⁴²Tb	141.939280858 ± 0.000752079	597 ms ± 17	1991	β⁺=100%; e⁺=96.8±0.4%; ε=3.2±0.4%; β⁺p=0.0022±1.1%
¹⁴²Tb^m	141.939280858 ± 0.000752079	303 ms ± 17	1986	IT=100%
¹⁴²Tbⁿ	141.939280858 ± 0.000752079	26 us ± 1	1989	IT=100%
¹⁴³Tb	142.935137332 ± 0.000055	12 s ± 1	1985	β⁺=100%
¹⁴³Tb^m	142.935137332 ± 0.000055	17 s ± 4	1986	β⁺ ?
¹⁴⁴Tb	143.933045000 ± 0.00003	~1 s	1982	β⁺=100%
¹⁴⁴Tb^m	143.933045000 ± 0.00003	4.25 s ± 0.15	1982	IT=66%; β⁺=34%
¹⁴⁴Tbⁿ	143.933045000 ± 0.00003	2.8 us ± 0.3	1996	IT=100%
¹⁴⁴Tb^p	143.933045000 ± 0.00003	670 ns ± 60	1996	IT=100%
¹⁴⁴Tb^q	143.933045000 ± 0.00003	<300 ns	1996	IT=100%
¹⁴⁵Tb	144.928717001 ± 0.000119051	30.9 s ± 0.6	1981	β⁺=100%
¹⁴⁵Tb^m	144.928717001 ± 0.000119051	Not-specified	1993	β⁺ ?
¹⁴⁶Tb	145.927252739 ± 0.000048159	8 s ± 4	1974	β⁺=100%
¹⁴⁶Tb^m	145.927252739 ± 0.000048159	24.1 s ± 0.5	1974	β⁺=100%
¹⁴⁶Tbⁿ	145.927252739 ± 0.000048159	1.18 ms ± 0.02	1989	IT=100%
¹⁴⁷Tb	146.924054620 ± 0.000008691	1.64 h ± 0.03	1969	β⁺=100%
¹⁴⁷Tb^m	146.924054620 ± 0.000008691	1.87 m ± 0.05	1987	β⁺=100%
¹⁴⁸Tb	147.924275476 ± 0.000013379	60 m ± 1	1960	β⁺=100%
¹⁴⁸Tb^m	147.924275476 ± 0.000013379	2.20 m ± 0.05	1973	β⁺=100%
¹⁴⁸Tbⁿ	147.924275476 ± 0.000013379	1.310 us ± 0.007	1980	IT=100%
¹⁴⁹Tb	148.923253792 ± 0.000003895	4.118 h ± 0.025	1950	β⁺=83.3±1.7%; α=16.7±1.7%
¹⁴⁹Tb^m	148.923253792 ± 0.000003895	4.16 m ± 0.04	1962	β⁺≈100%; α=0.022±0.3%
¹⁵⁰Tb	149.923664799 ± 0.000007912	3.48 h ± 0.16	1959	β⁺≈100%; α ?
¹⁵⁰Tb^m	149.923664799 ± 0.000007912	5.8 m ± 0.2	1993	β⁺≈100%; IT ?
¹⁵¹Tb	150.923108970 ± 0.000004395	17.609 h ± 0.001	1953	β⁺=99.9905±1.5%; α=0.0095±1.5%
¹⁵¹Tb^m	150.923108970 ± 0.000004395	25 s ± 3	1978	IT=93.4±2%; β⁺=6.6±2%
¹⁵²Tb	151.924081855 ± 0.000042955	17.5 h ± 0.1	1959	β⁺=100%; α ?
¹⁵²Tb^m	151.924081855 ± 0.000042955	960 ns ± 10	1972	IT=100%
¹⁵²Tbⁿ	151.924081855 ± 0.000042955	4.2 m ± 0.1	1971	IT=78.9±0.6%; β⁺=21.1±0.6%
¹⁵³Tb	152.923441694 ± 0.000004237	2.34 d ± 0.01	1957	β⁺=100%
¹⁵³Tb^m	152.923441694 ± 0.000004237	186 us ± 4	1965	IT=100%
¹⁵⁴Tb	153.924683681 ± 0.000048641	9.994 h ± 0.039	1972	β⁺=100%; β^- ?
¹⁵⁴Tb^m	153.924683681 ± 0.000048641	21.5 h ± 0.4	1950	β⁺≈100%; IT ?; β^- ?
¹⁵⁴Tbⁿ	153.924683681 ± 0.000048641	22.7 h ± 0.5	1972	β⁺≈100%; IT ?
¹⁵⁴Tb^p	153.924683681 ± 0.000048641	513 ns ± 42	1982	IT=100%
¹⁵⁵Tb	154.923509511 ± 0.000010552	5.32 d ± 0.06	1957	ε=100%
¹⁵⁶Tb	155.924754209 ± 0.000004044	5.35 d ± 0.10	1950	β⁺≈100%; β^- ?
¹⁵⁶Tb^m	155.924754209 ± 0.000004044	5.3 h ± 0.2	1950	IT=?; β⁺=?
¹⁵⁶Tbⁿ	155.924754209 ± 0.000004044	24.4 h ± 1.0	1970	IT=?; β^- ?
¹⁵⁷Tb	156.924031888 ± 0.000001092	71 y ± 7	1960	ε=100%
¹⁵⁸Tb	157.925419942 ± 0.00000136	180 y ± 11	1957	β⁺=83.4±0.7%; β^-=16.6±0.7%
¹⁵⁸Tb^m	157.925419942 ± 0.00000136	10.70 s ± 0.17	1957	IT≈100%; β^- ?; β⁺ ?
¹⁵⁸Tbⁿ	157.925419942 ± 0.00000136	400 us ± 40	1961	IT=100%
¹⁵⁹Tb	158.925353707 ± 0.000001184	Stable	1933	IS=100%
¹⁶⁰Tb	159.927174553 ± 0.000001191	72.3 d ± 0.2	1943	β^-=100%
¹⁶¹Tb	160.927576806 ± 0.000001308	6.948 d ± 0.005	1949	β^-=100%
¹⁶²Tb	161.929275400 ± 0.0000022	7.60 m ± 0.15	1965	β^-=100%
¹⁶²Tb^m	161.929275400 ± 0.0000022	10 m [Estimated]	2020	β^- ?; IT ?
¹⁶³Tb	162.930653609 ± 0.000004358	19.5 m ± 0.3	1966	β^-=100%
¹⁶⁴Tb	163.933327561 ± 0.000002	3.0 m ± 0.1	1968	β^-=100%
¹⁶⁴Tb^m	163.933327561 ± 0.000002	2 m [Estimated]	2020	β^- ?; IT ?
¹⁶⁵Tb	164.934955198 ± 0.000001654	2.11 m ± 0.10	1983	β^-=100%
¹⁶⁵Tb^m	164.934955198 ± 0.000001654	0.81 us ± 0.08	2017	IT=100%
¹⁶⁶Tb	165.937939727 ± 0.00000157	27.1 s ± 1.5	1996	β^-=100%
¹⁶⁶Tb^m	165.937939727 ± 0.00000157	3.5 us ± 0.4	2017	IT=100%
¹⁶⁷Tb	166.940007046 ± 0.000002071	18.9 s ± 1.6	1999	β^-=100%
¹⁶⁷Tb^m	166.940007046 ± 0.000002071	1.2 us ± 0.1	2017	IT=100%
¹⁶⁸Tb	167.943337074 ± 0.0000045	9.4 s ± 0.4	1999	β^-=100%
¹⁶⁸Tb^m	167.943337074 ± 0.0000045	0.71 us ± 0.03	2017	IT=100%
¹⁶⁹Tb	168.945807 ± 0.000322 [Estimated]	5.13 s ± 0.32	2012	β^-=100%; β^-n ?
¹⁷⁰Tb	169.949855 ± 0.000322 [Estimated]	960 ms ± 78	2012	β^-=100%; β^-n ?
¹⁷¹Tb	170.953011 ± 0.000429 [Estimated]	1.23 s ± 0.10	2012	β^-=100%; β^-n ?
¹⁷²Tb	171.957391 ± 0.000537 [Estimated]	760 ms ± 190	2012	β^-=100%; β^-n ?
¹⁷³Tb	172.960805 ± 0.000537 [Estimated]	400 ms >550ns [Estimated]	2018	β^- ?; β^-n ?
¹⁷⁴Tb	173.965679 ± 0.000537 [Estimated]	240 ms >550ns [Estimated]	2018	β^- ?; β^-n ?

Information Sources

1. PubChem
https://pubchem.ncbi.nlm.nih.gov
2. Atomic Mass Data Center (AMDC), International Atomic Energy Agency (IAEA)
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Tb
https://www-nds.iaea.org/amdc/
3. IUPAC Commission on Isotopic Abundances and Atomic Weights (CIAAW)
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http://www.ciaaw.org/bylaws.htm

Terbium
https://www.ciaaw.org/terbium.htm
4. Jefferson Lab, U.S. Department of Energy
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Please see citation and linking information https https://www.jlab.org/privacy-and-security-notice

Terbium
https://education.jlab.org/itselemental/ele065.html
5. Los Alamos National Laboratory, U.S. Department of Energy
LICENSE
https://about.lanl.gov/lanl-resources/web-policies/

Terbium
https://periodic.lanl.gov/65.shtml
6. NIST Physical Measurement Laboratory
LICENSE
https://www.nist.gov/pml/database-disclaimer

Terbium
https://physics.nist.gov/cgi-bin/Elements/elInfo.pl?element=65
7. IUPAC Periodic Table of the Elements and Isotopes (IPTEI)
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Copyright (c) 2020 International Union of Pure and Applied Chemistry. The International Union of Pure and Applied Chemistry (IUPAC) contribution within Pubchem is provided under a CC-BY-NC-ND 4.0 license, unless otherwise stated.
https://creativecommons.org/licenses/by-nc-nd/4.0/
https://doi.org/10.1515/pac-2015-0703
8. PubChem Elements
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https://www.nlm.nih.gov/copyright.html

Terbium

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