Thulium (Tm)
lanthanideSolid
Peso atomico standard
168,93422 uConfigurazione elettronica
[Xe] 6s2 4f13Punto di fusione
1544,85 °CPunto di ebollizione
1949,85 °CDensità
9320 kg/m³Stati di ossidazione
0, +1, +2, +3Elettronegatività (Pauling)
1,25Energia di ionizzazione (1ª)
6,184402 eVAnno della scoperta
1879Raggio atomico
175 pmDettagli
Thulium is a lanthanide rare-earth metal and the least abundant stable lanthanide in Earth’s crust. It is chemically typical of the series, forming mainly Tm³⁺ compounds with a high affinity for oxygen and halogens. The element is not scarce enough to be unattainable, but it is dispersed and difficult to separate from neighboring lanthanides. Its technological importance is concentrated in isotope sources, specialty lasers, and optical materials rather than bulk structural use.
Thulium can be isolated by reduction of the oxide with lanthanum metal or by calcium reduction of a closed container. The element is silver-gray, soft, malleable, and ductile, and can be cut with a knife. Twenty five isotopes are known, with atomic masses ranging from 152 to 176. Natural thulium, which is 100% 169Tm, is stable.
The name derives from Thule, the earliest name for the northernmost part of the civilized world—Scandinavia. It was discovered in 1879 by the Swedish chemist Per Theodor Cleve in a sample of erbium mineral. Thulium was first isolated by the American chemist Charles James in 1911.
Thulium was discovered by Per Theodor Cleve, a Swedish chemist, in 1879. Cleve used the same method Carl Gustaf Mosander used to discover lanthanum, erbium and terbium, he looked for impurities in the oxides of other rare earth elements. He started with erbia, the oxide of erbium (Er2O3), and removed all of the known contaminants. After further processing, he obtained two new materials, one brown and the other green. Cleve named the brown material holmia and the green material thulia. Holmia is the oxide of the element holmium and thulia is the oxide of the element thulium. Today, thulium 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 can contain as much as 0.007% thulium.
Named after Thule, the earliest name for Scandinavia. Discovered in 1879 by Cleve. Thulium occurs in small quantities along with other rare earths in a number of minerals. It is obtained commercially from monazite, which contains about 0.007% of the element. Thulium is the least abundant of the rare earth elements, but with new sources recently discovered, it is now considered to be about as rare as silver,gold, or cadmium.
Pure thulium is a soft, malleable, silvery metal. It slowly tarnishes in air as oxide forms on the surface and reacts more readily when heated. Like many lanthanides, it can be cut with a knife and is normally stored to limit oxidation.
Thulium has specialized uses where its nuclear or optical properties are useful. Neutron-activated ¹⁷⁰Tm produces ¹⁷⁰Tm, a portable gamma and X-ray source formerly used in industrial radiography and still of technical interest where compact sealed sources are suitable. Thulium-doped yttrium aluminium garnet, commonly written Y₃Al₅O₁₂:Tm, and other host crystals are used in solid-state lasers near the two-micrometre infrared region. Thulium-doped silica fibers are also used in fiber lasers and amplifiers. Small amounts may be used in research alloys and magnetic studies, but there is no large-volume elemental application.
Thulium is the least abundant of the naturally occurring rare earth elements. Metallic thulium is relatively expensive and has only recently become available. It currently has no commercial applications, although one of its isotopes, thulium-169, could be used as a radiation source for portable X-ray machines.
Thulium forms no commercially important compounds. Some of thulium's compounds include: thulium oxide (Tm2O3), thulium fluoride (TmF3) and thulium iodide (TmI3).
Because of the relatively high price of the metal, thulium has not yet found many practical applications. 169Tm bombarded in a nuclear reactor can be used as a radiation source in portable X-ray equipment. 171Tm is potentially useful as an energy source. Natural thulium also has possible use in ferrites (ceramic magnetic materials) used in microwave equipment, and can be used for doping fiber lasers. As with other lanthanides, thulium has a low-to-moderate acute toxic rating. It should be handled with care.
Isotopes in Industry
170Tm (with a half-life of about 130 days) is used in the petrochemical industry for industrial radiography to test welds in pipes and tanks [486] Industrial Applications of Sealed Radiation Sources and Alternative Non Nuclear Technologies, Final Report, 68-D-00-210, p. 37. Trinity Engineering Associates Ohio (2002)..
Isotopes in Medicine
167Tm (with a half-life of 9.2 days) is useful for tumor and bone studies [487] F. Tárkányi, A. Hermanne, S. Takács, B. Király, I. Spahn, A. V. Ignatyuk. Appl. Radiat. Isot.68, 250 (2010).. Stable 169Tm can be bombarded in a nuclear reactor to create 170Tm, via the 169Tm (n, γ) 170Tm reaction, which emits X-rays and has been used in portable X-ray equipment as a radiation source [488] D. Granero, J. Pérez-Calatayud, F. Ballester, A. J. Bos, J. Venselaar. Radiat. Prot. Dosimetry118, 11 (2006).. 170Tm has been used in high-dose-rate (HDR) brachytherapy [489] F. Ballester, D. Granero, J. Perez-Calatayud, J. L. Venselaar, M. J. Rivard. Med. Phys.37, 1629 (2010). and for use in radiosynovectomy of medium sized joints (Fig. IUPAC.69.1) [490] A. Polyak, T. Das, S. Chakraborty, R. Kiraly, G. Dabasi, R. P. Joba, C. Jakab, J. Thuroczy, Z. Postenyi, V. Haasz, G. Janoki, G. A. Janoki, M. R. A. Pillai, L. Balogh. Cancer Biother. Radiopharm.29, 330 (2014)..
Thulium chemistry is dominated by the +3 oxidation state. Thulium(III) oxide, Tm₂O₃, is the common oxide and is a useful starting material for preparing other salts and optical ceramics. Thulium(III) chloride, TmCl₃, and thulium(III) fluoride, TmF₃, are representative halides; the fluoride is sparingly soluble and useful in separations and fluoride materials. A +2 state is known in some strongly reducing solid compounds, but it is much less stable than Tm³⁺ in ordinary aqueous chemistry. In solution, Tm³⁺ salts are typically pale green to nearly colorless depending on concentration and ligand field.
See more information at the Thulium compound page.
Metallic thulium has low acute chemical toxicity compared with many heavy metals, but fine powder is a fire hazard and can react with air or moisture. Soluble thulium salts should be handled as toxic laboratory chemicals because rare-earth ions can affect biological processes at elevated exposure. Radioactive ¹⁷⁰Tm presents an external radiation hazard and an internal hazard if contamination occurs; sealed sources require isotope-specific controls.
Thulium occurs naturally only as a minor constituent of rare-earth minerals, especially minerals that contain the heavy lanthanides. Weathering releases it mainly as Tm³⁺, which tends to bind to clays, oxides, phosphates, and organic matter rather than remain highly mobile. It has no known biological role. Environmental concentrations are usually very low, so ecological effects are mainly a concern near rare-earth mining, processing, or disposal sites.
Thulium is obtained as a by-product of rare-earth extraction rather than mined for its own sake. Sources include ion-adsorption clays and minerals such as monazite and xenotime that contain small fractions of heavy rare earths. Separation relies on solvent extraction, ion exchange, and conversion through oxide or salt intermediates, with cost driven more by separation complexity than by absolute crustal scarcity. Demand is small and specialized, so supply is tied to broader rare-earth processing rather than an independent commodity chain. Recycling is limited because applications use small amounts in dispersed devices or sealed sources.
Found with other rare earths in the minerals gadolinite, euxenite, xenotime, and monazite. Monazite is often 50% rare earth by weight and 0.007% thulium.
Thulium is a rare cosmic element produced mainly by neutron-capture processes in evolved stars and stellar explosions. Its odd atomic number and position among the heavy lanthanides make it much less abundant than lighter rock-forming elements and less abundant than several neighboring rare earths. In planets and meteorites it follows refractory lithophile behavior and partitions with other rare-earth elements rather than forming native metal.
- Thulium is the least abundant lanthanide that has a stable isotope.
- Natural thulium is essentially all ¹⁶⁹Tm.
- ¹⁷⁰Tm can be made by neutron irradiation of ¹⁶⁹Tm.
- Thulium was named after Thule, a classical name associated with the far north.
- Despite its rarity among lanthanides, thulium is more abundant in Earth’s crust than silver.
Immagini
Proprietà
Fisiche
- Raggio atomico (empirico)
- 175 pm Confronta Raggio atomico (empirico) di tutti gli elementi →
- Raggio covalente
- 190 pm Confronta Raggio covalente di tutti gli elementi →
- Raggio di van der Waals
- 227 pm Confronta Raggio di van der Waals di tutti gli elementi →
- Densità
- 9320 kg/m³ Confronta Densità di tutti gli elementi →
- Volume molare
- 0,0181 L/mol
- Fase in condizioni STP
- Solido Confronta Fase in condizioni STP di tutti gli elementi →
- Punto di fusione
- 1544,85 °C Confronta Punto di fusione di tutti gli elementi →
- Punto di ebollizione
- 1949,85 °C Confronta Punto di ebollizione di tutti gli elementi →
- Capacità termica specifica
- 0,16 J/(g·K) Confronta Capacità termica specifica di tutti gli elementi →
- Capacità termica molare
- 27,03 J/(mol·K) Confronta Capacità termica molare di tutti gli elementi →
- Struttura cristallina
- Esagonale compatta Confronta Struttura cristallina di tutti gli elementi →
Chimiche
- Elettronegatività (Pauling)
- 1,25 Confronta Elettronegatività (Pauling) di tutti gli elementi →
- Affinità elettronica
- 1,029 eV
- Energia di ionizzazione (1ª)
- 6,184402 eV Confronta Energia di ionizzazione (1ª) di tutti gli elementi →
- Energia di ionizzazione (2ª)
- 12,065042 eV Confronta Energia di ionizzazione (2ª) di tutti gli elementi →
- Energia di ionizzazione (3ª)
- 23,660081 eV Confronta Energia di ionizzazione (3ª) di tutti gli elementi →
- Energia di ionizzazione (4ª)
- 42,410146 eV Confronta Energia di ionizzazione (4ª) di tutti gli elementi →
- Energia di ionizzazione (5ª)
- 65,400225 eV Confronta Energia di ionizzazione (5ª) di tutti gli elementi →
- Stati di ossidazione
- 0, +1, +2, +3 Confronta Stati di ossidazione di tutti gli elementi →
- Elettroni di valenza
- 3 Confronta Elettroni di valenza di tutti gli elementi →
- Configurazione elettronica
- [Xe] 6s2 4f13
Termodinamiche
- Calore di fusione
- 0,12437166 eV Confronta Calore di fusione di tutti gli elementi →
- Calore di vaporizzazione
- 1,979582 eV Confronta Calore di vaporizzazione di tutti gli elementi →
- Calore di sublimazione
- 2,404519 eV
- Calore di atomizzazione
- 2,404519 eV
- Entalpia di atomizzazione
- 2,406592 eV
Nucleari
- Protoni
- 69 Confronta Protoni di tutti gli elementi →
- Neutroni
- 100 Confronta Neutroni di tutti gli elementi →
- Isotopi noti
- 39 Confronta Isotopi noti di tutti gli elementi →
- Isotopi stabili
- 1 Confronta Isotopi stabili di tutti gli elementi →
- Isotopo più stabile
- Tm-169
- Anno della scoperta
- 1879
Abbondanza
- Abbondanza (crosta terrestre)
- 0,52 mg/kg Confronta Abbondanza (crosta terrestre) di tutti gli elementi →
- Abbondanza (oceano)
- 1,7 × 10−7 mg/L Confronta Abbondanza (oceano) di tutti gli elementi →
Struttura cristallina
- Costante reticolare a
- 354 pm
Struttura elettronica
- Elettroni per guscio
- 2, 8, 18, 31, 8, 2 Confronta Elettroni per guscio di tutti gli elementi →
Identificativi
- Numero CAS
- 7440-30-4 Confronta Numero CAS di tutti gli elementi →
- Simbolo di termine
- 2F°7/2
- InChI
- InChI=1S/Tm
- Chiave InChI
- FRNOGLGSGLTDKL-UHFFFAOYSA-N
Configurazione elettronica Misurato
Tm: 4f¹³ 6s²[Xe] 4f¹³ 6s²1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹³ 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 |
|---|---|---|---|
| 169 Stabile | 168,9342179 ± 0,0000022 | 100,0000% | Stabile |
Fase / Stato
Motivo: 1519,8 °C sotto il punto di fusione (1544,85 °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 69. Ordinamento per carica ionica crescente.
Righe disponibili ?
| Ione | Carica | Righe totali | Probabilità di transizione | Designazioni dei livelli |
|---|---|---|---|---|
| Tm I | 0 | 538 | 408 | 525 |
| Tm II | +1 | 267 | 13 | 13 |
| Tm III | +2 | 186 | 0 | 0 |
Livelli disponibili ?
| Ione | Carica | Livelli |
|---|---|---|
| Tm I | 0 | 631 |
| Tm II | +1 | 367 |
| Tm III | +2 | 128 |
| Tm IV | +3 | 8 |
| Tm V | +4 | 2 |
| Tm VI | +5 | 2 |
| Tm VII | +6 | 2 |
| Tm VIII | +7 | 2 |
| Tm IX | +8 | 2 |
| Tm X | +9 | 2 |
Raggi ionici
| Carica | Coordinazione | Spin | Raggio |
|---|---|---|---|
| +2 | 6 | N/D | 103 pm |
| +2 | 7 | N/D | 109.00000000000001 pm |
| +3 | 6 | N/D | 88 pm |
| +3 | 8 | N/D | 99.4 pm |
| +3 | 9 | N/D | 105.2 pm |
Composti
Isotopi (1)
| Numero di massa | Massa atomica (u) | Abbondanza naturale | Emivita | Modalità di decadimento | |
|---|---|---|---|---|---|
| 169 Stabile | 168,9342179 ± 0,0000022 | 100,0000% | Stabile | stable |
Proprietà estese
Raggi covalenti (dati estesi)
- Raggio covalente (Pyykkö)
- 164 pm
- Raggio covalente (Pyykkö, legame doppio)
- 131 pm
Raggi di van der Waals
- Alvarez
- 279 pm
- UFF
- 337,4 pm
- MM3
- 267 pm
Raggi atomici e metallici
- Raggio atomico (Rahm)
- 271 pm
Scale di numerazione
- Mendeleev
- 37
- Pettifor
- 22
- Glawe
- 20
Scale di elettronegatività
- Ghosh
- 0
- Miedema
- 3
- Gunnarsson–Lundqvist
- 6
- Robles–Bartolotti
- 5
Polarizzabilità e dispersione
- Polarizzabilità dipolare
- 144 a.u.
- Polarizzabilità dipolare (inc.)
- 15 a.u.
- C₆ (Gould–Bučko)
- 2020 Ha·Bohr6
Parametri di Miedema
- Volume molare di Miedema
- 18,12 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 | 1818,15 K |
| Punto di ebollizione | 2223,15 K |
Categorie degli stati di ossidazione
Dati di riferimento avanzati
Costanti di schermaggio (13)
| n | Orbitale | σ |
|---|---|---|
| 1 | s | 1,3437 |
| 2 | p | 4,3588 |
| 2 | s | 18,0522 |
| 3 | d | 13,6257 |
| 3 | p | 20,5239 |
| 3 | s | 21,0816 |
| 4 | d | 36,056 |
| 4 | f | 40,366 |
| 4 | p | 33,012 |
| 4 | s | 31,8624 |
Dettaglio dei raggi cristallini (5)
| Carica | CN | Spin | rcrystal (pm) | Origine |
|---|---|---|---|---|
| 2 | VI | 117 | ||
| 2 | VII | 123 | ||
| 3 | VI | 102 | from r^3 vs V plots, | |
| 3 | VIII | 113,4 | from r^3 vs V plots, | |
| 3 | IX | 119,2 | from r^3 vs V plots, |
Modalità di decadimento degli isotopi (58)
| Isotopo | Modalità | Intensità |
|---|---|---|
| 144 | p | — |
| 144 | B+ | — |
| 145 | p | 100% |
| 146 | p | 100% |
| 146 | B+ | — |
| 146 | B+p | — |
| 147 | B+ | 85% |
| 147 | p | 15% |
| 148 | B+ | 100% |
| 148 | B+p | — |
Fattori di diffusione dei raggi X (514)
| Energia (eV) | f₁ | f₂ |
|---|---|---|
| 10 | — | 0,17918 |
| 10,1617 | — | 0,18356 |
| 10,3261 | — | 0,18805 |
| 10,4931 | — | 0,19265 |
| 10,6628 | — | 0,19737 |
| 10,8353 | — | 0,2022 |
| 11,0106 | — | 0,20714 |
| 11,1886 | — | 0,21221 |
| 11,3696 | — | 0,21741 |
| 11,5535 | — | 0,22273 |
Dati aggiuntivi
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
5.2×10-1 milligrams per kilogram
Riferimenti (1)
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
1.7×10-7 milligrams per liter
Riferimenti (1)
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.
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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 Thulium.
The element property data was retrieved from publications.