Terbium (Tb)
lanthanideSolid
Peso atomico standard
158,92535 uConfigurazione elettronica
[Xe] 6s2 4f9Punto di fusione
1355,85 °CPunto di ebollizione
3229,85 °CDensità
8230 kg/m³Stati di ossidazione
0, +1, +2, +3, +4Elettronegatività (Pauling)
N/DEnergia di ionizzazione (1ª)
5,8638 eVAnno della scoperta
1843Raggio atomico
175 pmDettagli
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.
Pure terbium is a soft, silvery-gray metal. It is malleable enough to be cut and, like many lanthanides, slowly tarnishes in air as surface oxides form. It has more than one solid allotrope, with a structural change at elevated temperature.
Terbium is used mainly in small amounts where its optical or magnetic properties are valuable. Tb³⁺ activators provide green emission in phosphors for lighting, displays, and some X-ray imaging materials. Terbium is also a component of Terfenol-D, a terbium-dysprosium-iron magnetostrictive alloy used in actuators, sonar transducers, and vibration-control devices. In research and specialized instruments, terbium compounds are used as luminescent probes and magnetic materials.
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.
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] 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).. 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] 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).. 161Tb is being used for imaging as it allows for on-line monitoring of its distribution using gamma cameras [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).. 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] 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..
Terbium most commonly forms trivalent compounds containing Tb³⁺. Representative materials include terbium(III) oxide, Tb₂O₃, terbium(III) chloride, TbCl₃, and terbium(III) fluoride, TbF₃. Unlike many lanthanides, terbium also has accessible tetravalent chemistry in strongly oxidizing oxide and fluoride environments; terbium(IV) oxide, TbO₂, is a well established example. Mixed-valence oxides and doped host lattices are important because they tune luminescence, oxygen storage, and magnetic behavior.
See more information at the Terbium compound page.
Metallic terbium is not highly toxic in ordinary handling, but powders can be a fire and dust hazard, and soluble terbium salts should be treated as harmful laboratory chemicals. Fine metal reacts more readily with air and moisture than bulk pieces. Terbium has no known biological role. Commercial terbium is essentially stable isotopically; radiological hazards apply only to artificially produced radioactive isotopes or activated materials.
Little is known of the toxicity of terbium. It should be handled with care as with other lanthanide element
Terbium is a dispersed lithophile element found in rare-earth minerals such as monazite, bastnäsite, xenotime, and ion-adsorption clays. In soils and waters it is generally immobile because Tb³⁺ binds strongly to phosphates, carbonates, oxides, and organic matter. Natural concentrations are low, and biological uptake is limited. Environmental concern is usually associated with mining, acid leaching, and waste handling rather than with terbium metal itself.
Terbium is produced as a separated rare-earth product, not mined alone. Ores and concentrates are processed to dissolve mixed rare earths, then solvent extraction or ion exchange separates terbium from chemically similar lanthanides. Supply is constrained by the low abundance of terbium in many deposits, the complexity of separation, and dependence on rare-earth refining capacity. Demand is driven by phosphors and magnetostrictive alloys, but use per device is usually small. Recycling is technically possible from phosphor powders and some magnets or alloys, yet collection and separation are often limiting.
Found with other rare earths in monazite sand, which typically contain 0.03% terbium. Other sources are xenotime and euxenite, both of which are oxide mixtures that can contain up to 1% terbium.
Terbium is a heavy rare-earth element made mainly by neutron-capture nucleosynthesis in earlier generations of stars, with contributions from slow and rapid neutron-capture processes. It is far less abundant cosmically than iron-group elements and lighter rock-forming elements. In planetary materials it follows other trivalent lanthanides and concentrates in refractory mineral phases rather than volatile reservoirs.
- Terbium has only one stable natural isotope, ¹⁵⁹Tb.
- Its name comes from Ytterby, the Swedish locality linked to several rare-earth element names.
- Tb³⁺ emission is commonly used as a green reference in luminescence spectroscopy.
- Terfenol-D takes its name from terbium, iron, Naval Ordnance Laboratory, and dysprosium.
- Terbium can form stable Tb⁴⁺ in oxides more readily than most lanthanides.
Immagini
Proprietà
Fisiche
- Raggio atomico (empirico)
- 175 pm Confronta Raggio atomico (empirico) di tutti gli elementi →
- Raggio covalente
- 194 pm Confronta Raggio covalente di tutti gli elementi →
- Raggio di van der Waals
- 221 pm Confronta Raggio di van der Waals di tutti gli elementi →
- Densità
- 8230 kg/m³ Confronta Densità di tutti gli elementi →
- Volume molare
- 0,0192 L/mol
- Fase in condizioni STP
- Solido Confronta Fase in condizioni STP di tutti gli elementi →
- Punto di fusione
- 1355,85 °C Confronta Punto di fusione di tutti gli elementi →
- Punto di ebollizione
- 3229,85 °C Confronta Punto di ebollizione di tutti gli elementi →
- Conducibilità termica
- 11,1 W/(m·K) Confronta Conducibilità termica di tutti gli elementi →
- Capacità termica specifica
- 0,182 J/(g·K) Confronta Capacità termica specifica di tutti gli elementi →
- Capacità termica molare
- 28,91 J/(mol·K) Confronta Capacità termica molare di tutti gli elementi →
- Struttura cristallina
- Esagonale compatta Confronta Struttura cristallina di tutti gli elementi →
Chimiche
- Affinità elettronica
- 1,124 eV
- Energia di ionizzazione (1ª)
- 5,8638 eV Confronta Energia di ionizzazione (1ª) di tutti gli elementi →
- Energia di ionizzazione (2ª)
- 11,51304 eV Confronta Energia di ionizzazione (2ª) di tutti gli elementi →
- Energia di ionizzazione (3ª)
- 21,820075 eV Confronta Energia di ionizzazione (3ª) di tutti gli elementi →
- Energia di ionizzazione (4ª)
- 39,330135 eV Confronta Energia di ionizzazione (4ª) di tutti gli elementi →
- Energia di ionizzazione (5ª)
- 66,500229 eV Confronta Energia di ionizzazione (5ª) di tutti gli elementi →
- Stati di ossidazione
- 0, +1, +2, +3, +4 Confronta Stati di ossidazione di tutti gli elementi →
- Elettroni di valenza
- 3 Confronta Elettroni di valenza di tutti gli elementi →
- Configurazione elettronica
- [Xe] 6s2 4f9
Termodinamiche
- Calore di fusione
- 0,1119345 eV Confronta Calore di fusione di tutti gli elementi →
- Calore di vaporizzazione
- 3,016013 eV Confronta Calore di vaporizzazione di tutti gli elementi →
- Calore di sublimazione
- 4,031715 eV
- Calore di atomizzazione
- 4,031715 eV
- Entalpia di atomizzazione
- 4,028605 eV
Nucleari
- Protoni
- 65 Confronta Protoni di tutti gli elementi →
- Neutroni
- 94 Confronta Neutroni di tutti gli elementi →
- Isotopi noti
- 40 Confronta Isotopi noti di tutti gli elementi →
- Isotopi stabili
- 1 Confronta Isotopi stabili di tutti gli elementi →
- Isotopo più stabile
- Tb-159
- Anno della scoperta
- 1843
Abbondanza
- Abbondanza (crosta terrestre)
- 1,2 mg/kg Confronta Abbondanza (crosta terrestre) di tutti gli elementi →
- Abbondanza (oceano)
- 1,4 × 10−7 mg/L Confronta Abbondanza (oceano) di tutti gli elementi →
Struttura cristallina
- Costante reticolare a
- 360 pm
Struttura elettronica
- Elettroni per guscio
- 2, 8, 18, 27, 8, 2 Confronta Elettroni per guscio di tutti gli elementi →
Identificativi
- Numero CAS
- 7440-27-9 Confronta Numero CAS di tutti gli elementi →
- Simbolo di termine
- 6H°15/2
- InChI
- InChI=1S/Tb
- Chiave InChI
- GZCRRIHWUXGPOV-UHFFFAOYSA-N
Configurazione elettronica Misurato
Tb: 4f⁹ 6s²[Xe] 4f⁹ 6s²1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f⁹ 6s²Modello atomico
Gli isotopi modificano il numero di neutroni, la massa e la stabilità — non la configurazione elettronica di un atomo neutro.
Modello atomico schematico, non in scala.
Impronta atomica
Spettro di emissione / assorbimento
Distribuzione isotopica
| Numero di massa | Massa atomica (u) | Abbondanza naturale | Emivita |
|---|---|---|---|
| 159 Stabile | 158,9253547 ± 0,0000019 | 100,0000% | Stabile |
Fase / Stato
Motivo: 1330,8 °C sotto il punto di fusione (1355,85 °C)
Schema non in scala
Punti di transizione di fase
Energie di transizione
Energia necessaria per fondere 1 mol al punto di fusione
Energia necessaria per vaporizzare 1 mol al punto di ebollizione
Energia necessaria per sublimare 1 mol al punto di sublimazione
Densità
In condizioni standard
In condizioni standard
Spettri atomici
Sono visualizzati 10 di 65. Ordinamento per carica ionica crescente.
Righe disponibili ?
| Ione | Carica | Righe totali | Probabilità di transizione | Designazioni dei livelli |
|---|---|---|---|---|
| Tb I | 0 | 248 | 0 | 10 |
| Tb II | +1 | 424 | 8 | 18 |
| Tb IV | +3 | 48 | 0 | 0 |
Livelli disponibili ?
| Ione | Carica | Livelli |
|---|---|---|
| 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 |
Raggi ionici
| Carica | Coordinazione | Spin | Raggio |
|---|---|---|---|
| +3 | 6 | N/D | 92.30000000000001 pm |
| +3 | 7 | N/D | 98 pm |
| +3 | 8 | N/D | 104 pm |
| +3 | 9 | N/D | 109.5 pm |
| +4 | 6 | N/D | 76 pm |
| +4 | 8 | N/D | 88 pm |
Composti
Isotopi (1)
| Numero di massa | Massa atomica (u) | Abbondanza naturale | Emivita | Modalità di decadimento | |
|---|---|---|---|---|---|
| 159 Stabile | 158,9253547 ± 0,0000019 | 100,0000% | Stabile | stable |
Proprietà estese
Raggi covalenti (dati estesi)
- Raggio covalente (Pyykkö)
- 168 pm
- Raggio covalente (Pyykkö, legame doppio)
- 135 pm
Raggi di van der Waals
- Alvarez
- 279 pm
- UFF
- 345,1 pm
- MM3
- 270 pm
Raggi atomici e metallici
- Raggio atomico (Rahm)
- 276 pm
Scale di numerazione
- Mendeleev
- 29
- Pettifor
- 26
- Glawe
- 25
Scale di elettronegatività
- Ghosh
- 0
- Miedema
- 3
- Gunnarsson–Lundqvist
- 4
- Robles–Bartolotti
- 3
Polarizzabilità e dispersione
- Polarizzabilità dipolare
- 170 a.u.
- Polarizzabilità dipolare (inc.)
- 20 a.u.
- C₆ (Gould–Bučko)
- 2590 Ha·Bohr6
Parametri di Miedema
- Volume molare di Miedema
- 19,32 cm3/mol
- Densità elettronica di Miedema
- 2
Rischio di approvvigionamento ed economia
- Concentrazione della produzione
- 97
- Rischio relativo di approvvigionamento
- 10
- Distribuzione delle riserve
- 50
- Stabilità politica (principale produttore)
- 24
- Stabilità politica (principale detentore di riserve)
- 24
Transizioni di fase e allotropi
| Punto di fusione | 1632,15 K |
| Punto di ebollizione | 3503,15 K |
Categorie degli stati di ossidazione
Dati di riferimento avanzati
Costanti di schermaggio (13)
| n | Orbitale | 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 |
Dettaglio dei raggi cristallini (6)
| Carica | CN | Spin | rcrystal (pm) | Origine |
|---|---|---|---|---|
| 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 |
Modalità di decadimento degli isotopi (63)
| Isotopo | Modalità | Intensità |
|---|---|---|
| 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% |
Fattori di diffusione dei raggi X (514)
| Energia (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 |
Dati aggiuntivi
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
1.2 milligrams per kilogram
Riferimenti (1)
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
1.4×10-7 milligrams per liter
Riferimenti (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.
Riferimenti (1)
- [6] Terbium https://periodic.lanl.gov/65.shtml
Riferimenti
(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.
Thomas Jefferson National Accelerator Facility (Jefferson Lab) is one of 17 national laboratories funded by the U.S. Department of Energy. The lab's primary mission is to conduct basic research of the atom's nucleus using the lab's unique particle accelerator, known as the Continuous Electron Beam Accelerator Facility (CEBAF). For more information visit https://www.jlab.org/
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.