Tantalum (Ta)
transition-metalSolid
Peso atomico standard
180,94788 uConfigurazione elettronica
[Xe] 6s2 4f14 5d3Punto di fusione
3016,85 °CPunto di ebollizione
5457,85 °CDensità
1,64e+4 kg/m³Stati di ossidazione
−3, −1, 0, +1, +2, +3, +4, +5Elettronegatività (Pauling)
1,5Energia di ionizzazione (1ª)
7,549571 eVAnno della scoperta
1802Raggio atomico
145 pmDettagli
Tantalum is a dense, refractory transition metal in group 5, closely associated geologically and chemically with niobium. It is noted for exceptional resistance to corrosion, a very high melting point, and the stable, high-permittivity oxide film that forms on its surface. Most natural tantalum is ¹⁸¹Ta, with a small contribution from the long-lived nuclear isomer ¹⁸⁰ᵐTa. Its chemistry is dominated by the +5 oxidation state.
Tantalum is a gray, heavy, and very hard metal. When pure, it is ductile and can be drawn into fine wire, which is used as a filament for evaporating metals such as aluminum. Tantalum is almost completely immune to chemical attack at temperatures below 150°C, and is attacked only by hydrofluoric acid, acidic solutions containing the fluoride ion, and free sulfur trioxide. Alkalis attack it only slowly. At high temperatures, tantalum becomes much more reactive. The element has a melting point exceeded only by tungsten and rhenium. Tantalum is used to make a variety of alloys with desirable properties such as high melting point, high strength, good ductility, etc. Tantalum has a good "gettering" ability at high temperatures, and tantalum oxide films are stable and have good rectifying and dielectric properties.
The name derives from the Greek mythological character Tantalus who was banished to Hades, the region of lost souls where he was placed up to his chin in water, which receded whenever he tried to drink it, and under branches of fruit, which drew back whenever he tried to pick their fruit. This name was selected because of the insolubility of tantalum in acids; thus, when placed in the midst of acids, it is incapable of taking any of them up. Tantalum was discovered by the Swedish chemist and mineralogist Anders- Gustav Ekeberg in 1802.
Tantalum was discovered by Anders Gustaf Ekenberg, a Swedish chemist, in 1802 in minerals obtained from Ytterby, Sweden. Many scientists believed that he had only discovered an allotrope of niobium, an element that is chemically similar to tantalum. The issue was finally settled in 1866 when, Jean Charles Galissard de Marignac, a Swiss chemist, proved that tantalum and niobium were two distinct elements. The first relatively pure samples of tantalum were first produced in 1907. Today, tantalum is primarily obtained from the minerals columbite ((Fe, Mn, Mg)(Nb, Ta)2O6), tantalite ((Fe, Mn)(Ta, Nb)2O6) and euxenite ((Y, Ca, Er, La, Ce, U, Th)(Nb, Ta, Ti)2O6).
Named after Tantalos, a Greek a mythological character, father of Niobe. Discovered in 1802 by Ekeberg, but many chemists thought niobium and tantalum were identical elements until Rowe in 1844, and Marignac, in 1866, showed that niobic and tantalic acids were two different acids. The early investigators only isolated the impure metal. The first relatively pure ductile tantalum was produced by von Bolton in 1903. Tantalum occurs principally in the mineral columbite-tantalite.
Pure tantalum is a hard, heavy, lustrous metal with a gray to blue-gray metallic surface. It is ductile when sufficiently pure but becomes less workable when contaminated by oxygen, nitrogen, hydrogen, or carbon. A thin oxide film passivates the surface in air.
Tantalum is widely used in solid electrolytic capacitors, where a porous metal anode and a thin tantalum pentoxide dielectric provide high capacitance per volume. It is also used in corrosion-resistant chemical equipment, heat exchangers, surgical implants, and high-temperature furnace parts. Tantalum carbide is important in hard materials, and tantalum additions improve some nickel- and cobalt-base superalloys. Because it absorbs little from body fluids and is corrosion resistant, the metal has had longstanding biomedical applications.
Tantalum is a strong, ductile metal that is nearly immune to chemical attack at room temperatures. It can be drawn into a fine wire that is used to evaporate metals, such as aluminum. It has a high melting point and is frequently used as a substitute for platinum, which is more expensive. Tantalum is used to make components for chemical plants, nuclear power plants, airplanes and missiles. Tantalum does not react with bodily fluids and is used to make surgical equipment. Tantalum also does not irritate the body and is used to make surgical sutures as well as implants, such as artificial joints and cranial plates. Tantalum is alloyed with steel to increase steel's ductility, strength and melting point.
Tantalum pentoxide (Ta2O5), one of tantalum's compounds, is a dielectric material and is used to make capacitors. It is also used to make a glass with a high index of refraction that is used in camera lenses. A composite consisting of tantalum carbide (TaC) and graphite is one of the hardest materials known and is used on the cutting edges of high-speed machine tools.
Scientists at Los Alamos have produced a tantalum carbide graphite composite material, which is said to be one of the hardest materials ever made. The compound has a melting point of 3738°C. Tantalum is used to make electrolytic capacitors and vacuum furnace parts, which account for about 60% of its use. The metal is also widely used to fabricate chemical process equipment, nuclear reactors, aircraft, and missile parts. Tantalum is completely immune to body liquids and is a nonirritating material. It has, therefore, found wide use in making surgical appliances. Tantalum oxide is used to make special glass with high index of refraction for camera lenses. The metal has many other uses.
Isotopes in Medicine
178 Ta (with a half-life of 9.3 min) is used in medical studies, such as first-pass radionuclide angiography of mice, to better understand cardiovascular disease. Radionuclide angiography uses a pinhole lens fitted to a high-speed multiwire proportional camera and a n(178W)/n(178Ta) amount-ratio generator for minimally invasive quantification of murine ventricular (heart) functions (Fig. IUPAC.73.1) [506] J. Lacy, T. Nanavaty, D. Dai, N. Nayak, N. Haynes, C. Martin. J. Nucl. Cardiol.8, 171 (2001)., [507] C. J. Hartley, G. E. Taffet, A. K. Reddy, M. L. Entman, L. H. Michael. ILAR J.43, 147 (2002).. The multiwire gamma camera has a 178Ta generator incorporated in its housing, and it provides portable and laboratory ventricular function assessments for cardiovascular patients [507] C. J. Hartley, G. E. Taffet, A. K. Reddy, M. L. Entman, L. H. Michael. ILAR J.43, 147 (2002)., [508] J. L. Lacy, A. D. LeBlanc, J. W. Babich, M. W. Bungo, L. A. Latson, R. M. Lewis, L. R. Poliner, R. H. Jones, P. C. Johnson. J. Nucl. Med.25, 1003 (1984).. Intravenous injections of 178Ta are used in gated equilibrium blood pool imaging [509] R. A. Wilson, S. Y. Kopiwoda, R. J. Callahan, R. H. Moore, C. A. Boucher, H. Manspeaker, F. P. Castronovo, H. W. Strauss. Eur. J. Nucl. Med. Mol. Imaging13, 82 (1987).. 183Ta (with a half-life of 5.1 days) has potential for use in radionuclide pharmaceuticals and as a tracer for toxicity studies of ecosystems [510] N. Shigeta, R. M. Lambrecht, H. Matsuoka, A. Osa, M. Koizumi, K. Kobayashi, M. Izumo, K. Hashimoto, T. Sekine. Appl. Radiat. Isot.47, 171 (1996)..
Isotopes Used as a Source of Radioactive Isotope(s)
181Ta is used to produce 178W, which decays to 178Ta via the reaction 181Ta (p, 4 n) 178W, which is followed by a subsequent electron capture decay reaction of 178W to finally yield 178Ta. 178Ta is important for medical studies as noted in Section 4.73.1.
Tantalum forms strongly oxophilic compounds and is most stable in the +5 oxidation state. Tantalum pentoxide, Ta₂O₅, is the most important oxide and forms the dielectric film used in capacitors. Tantalum pentachloride, TaCl₅, is a volatile chloride used in synthesis and deposition chemistry. Tantalates contain TaO₆ octahedra in many minerals and ceramic materials. Lower oxidation states exist in halides and cluster compounds, but they are less common in ordinary aqueous chemistry. Tantalum carbide, TaC, is an extremely hard refractory ceramic.
See more information at the Tantalum compound page.
Massive tantalum metal is generally of low chemical toxicity and is valued for biocompatibility, but fine powder can burn and should be treated as a combustible metal dust. Soluble tantalum compounds are uncommon but should not be assumed harmless. Processing hazards often come from associated acids, fluorides, chlorides, and fine particulates rather than from the bulk metal itself. Natural tantalum is only very weakly radioactive because of trace ¹⁸⁰ᵐTa.
Tantalum occurs in resistant oxide minerals and is not abundant in surface waters. Weathering can move small amounts in heavy-mineral sediments, while much remains in insoluble phases. It has no known essential biological role. Environmental concerns are usually linked to mining, mineral concentration, tailings, and the handling of associated elements rather than to high mobility of tantalum ions in natural waters.
Tantalum is produced mainly from tantalite- and columbite-bearing ores, from complex lithium-cesium-tantalum pegmatites, and as a by-product of tin or lithium mineral processing. Separation from niobium is a central refining step because the two elements have similar chemistry. Demand is strongly influenced by electronics, especially capacitors, but superalloys, carbides, and corrosion-resistant equipment also matter. Supply can be constrained by ore concentration, co-production relationships, conflict-mineral controls, and the need for specialized refining. Recycling from capacitor scrap and superalloy residues contributes but does not fully replace mined supply.
Tantalum ores are found in Australia, Brazil, Mozambique, Thailand, Portugal, Nigeria, Zaire, and Canada.
Tantalum is a rare heavy element in the cosmos. Its stable and long-lived isotopes are made mainly by neutron-capture processes in earlier generations of stars, with contributions from slow and rapid capture pathways. In planetary materials it is lithophile and refractory, so it concentrates in silicate reservoirs and resists volatilization during high-temperature condensation.
- Tantalum and niobium are so similar chemically that their separation shaped much of their early metallurgy.
- ¹⁸⁰ᵐTa is the rarest naturally occurring long-lived nuclear isomer known.
- The dielectric layer in tantalum capacitors is grown directly from the metal surface.
- Tantalum resists many acids but is attacked by hydrofluoric acid and fluoride-containing mixtures.
- Its name refers to Tantalus, reflecting the early difficulty of dissolving its oxide.
Immagini
Proprietà
Fisiche
- Raggio atomico (empirico)
- 145 pm Confronta Raggio atomico (empirico) di tutti gli elementi →
- Raggio covalente
- 170 pm Confronta Raggio covalente di tutti gli elementi →
- Raggio di van der Waals
- 217 pm Confronta Raggio di van der Waals di tutti gli elementi →
- Raggio metallico
- 134 pm Confronta Raggio metallico di tutti gli elementi →
- Densità
- 1,64 × 104 kg/m³ Confronta Densità di tutti gli elementi →
- Volume molare
- 0,0109 L/mol
- Fase in condizioni STP
- Solido Confronta Fase in condizioni STP di tutti gli elementi →
- Punto di fusione
- 3016,85 °C Confronta Punto di fusione di tutti gli elementi →
- Punto di ebollizione
- 5457,85 °C Confronta Punto di ebollizione di tutti gli elementi →
- Conducibilità termica
- 57,5 W/(m·K) Confronta Conducibilità termica di tutti gli elementi →
- Capacità termica specifica
- 0,14 J/(g·K) Confronta Capacità termica specifica di tutti gli elementi →
- Capacità termica molare
- 25,36 J/(mol·K) Confronta Capacità termica molare di tutti gli elementi →
- Struttura cristallina
- Cubica a corpo centrato Confronta Struttura cristallina di tutti gli elementi →
Chimiche
- Elettronegatività (Pauling)
- 1,5 Confronta Elettronegatività (Pauling) di tutti gli elementi →
- Elettronegatività (Allen)
- 1,34
- Affinità elettronica
- 0,322 eV
- Energia di ionizzazione (1ª)
- 7,549571 eV Confronta Energia di ionizzazione (1ª) di tutti gli elementi →
- Energia di ionizzazione (2ª)
- 16,200056 eV Confronta Energia di ionizzazione (2ª) di tutti gli elementi →
- Energia di ionizzazione (3ª)
- 23,10008 eV Confronta Energia di ionizzazione (3ª) di tutti gli elementi →
- Energia di ionizzazione (4ª)
- 35,00012 eV Confronta Energia di ionizzazione (4ª) di tutti gli elementi →
- Energia di ionizzazione (5ª)
- 48,272166 eV Confronta Energia di ionizzazione (5ª) di tutti gli elementi →
- Stati di ossidazione
- −3, −1, 0, +1, +2, +3, +4, +5 Confronta Stati di ossidazione di tutti gli elementi →
- Elettroni di valenza
- 5 Confronta Elettroni di valenza di tutti gli elementi →
- Configurazione elettronica
- [Xe] 6s2 4f14 5d3
Termodinamiche
- Calore di fusione
- 0,37902265 eV Confronta Calore di fusione di tutti gli elementi →
- Calore di vaporizzazione
- 7,804322 eV Confronta Calore di vaporizzazione di tutti gli elementi →
- Calore di sublimazione
- 8,104887 eV
- Calore di atomizzazione
- 8,104887 eV
- Entalpia di atomizzazione
- 8,104887 eV
Nucleari
- Protoni
- 73 Confronta Protoni di tutti gli elementi →
- Neutroni
- 108 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
- Ta-181
- Anno della scoperta
- 1802
Abbondanza
- Abbondanza (crosta terrestre)
- 2 mg/kg Confronta Abbondanza (crosta terrestre) di tutti gli elementi →
- Abbondanza (oceano)
- 2 × 10−6 mg/L Confronta Abbondanza (oceano) di tutti gli elementi →
Struttura cristallina
- Costante reticolare a
- 331 pm
Struttura elettronica
- Elettroni per guscio
- 2, 8, 18, 32, 11, 2 Confronta Elettroni per guscio di tutti gli elementi →
Identificativi
- Numero CAS
- 7440-25-7 Confronta Numero CAS di tutti gli elementi →
- Simbolo di termine
- 4F3/2
- InChI
- InChI=1S/Ta
- Chiave InChI
- GUVRBAGPIYLISA-UHFFFAOYSA-N
Configurazione elettronica Misurato
Ta: 4f¹⁴ 5d³ 6s²[Xe] 4f¹⁴ 5d³ 6s²1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d³ 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 |
|---|---|---|---|
| 181 Stabile | 180,9479958 ± 0,000002 | 99,9880% | Stabile |
Fase / Stato
Motivo: 2991,8 °C sotto il punto di fusione (3016,85 °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 73. Ordinamento per carica ionica crescente.
Righe disponibili ?
| Ione | Carica | Righe totali | Probabilità di transizione | Designazioni dei livelli |
|---|---|---|---|---|
| Ta I | 0 | 526 | 200 | 510 |
| Ta II | +1 | 141 | 0 | 13 |
| Ta IV | +3 | 83 | 0 | 0 |
| Ta V | +4 | 12 | 0 | 0 |
Livelli disponibili ?
| Ione | Carica | Livelli |
|---|---|---|
| Ta I | 0 | 301 |
| Ta II | +1 | 134 |
| Ta III | +2 | 2 |
| Ta IV | +3 | 2 |
| Ta V | +4 | 2 |
| Ta VI | +5 | 2 |
| Ta VII | +6 | 2 |
| Ta VIII | +7 | 2 |
| Ta IX | +8 | 2 |
| Ta X | +9 | 2 |
Raggi ionici
| Carica | Coordinazione | Spin | Raggio |
|---|---|---|---|
| +3 | 6 | N/D | 72 pm |
| +4 | 6 | N/D | 68 pm |
| +5 | 6 | N/D | 64 pm |
| +5 | 7 | N/D | 69 pm |
| +5 | 8 | N/D | 74 pm |
Composti
Isotopi (1)
| Numero di massa | Massa atomica (u) | Abbondanza naturale | Emivita | Modalità di decadimento | |
|---|---|---|---|---|---|
| 181 Stabile | 180,9479958 ± 0,000002 | 99,9880% ± 0,0003% | Stabile | stable |
Proprietà estese
Raggi covalenti (dati estesi)
- Raggio covalente (Pyykkö)
- 146 pm
- Raggio covalente (Pyykkö, legame doppio)
- 126 pm
- Raggio covalente (Pyykkö, legame triplo)
- 119 pm
Raggi di van der Waals
- Batsanov
- 220 pm
- Alvarez
- 253 pm
- UFF
- 317 pm
- MM3
- 243 pm
Raggi atomici e metallici
- Raggio atomico (Rahm)
- 258 pm
- Raggio metallico (C12)
- 146 pm
Scale di numerazione
- Mendeleev
- 49
- Pettifor
- 53
- Glawe
- 52
Scale di elettronegatività
- Ghosh
- 0
- Miedema
- 4
- Gunnarsson–Lundqvist
- 5
- Robles–Bartolotti
- 4
Polarizzabilità e dispersione
- Polarizzabilità dipolare
- 74 a.u.
- Polarizzabilità dipolare (inc.)
- 20 a.u.
- C₆ (Gould–Bučko)
- 887 Ha·Bohr6
Parametri di Miedema
- Volume molare di Miedema
- 10,81 cm3/mol
- Densità elettronica di Miedema
- 4
Rischio di approvvigionamento ed economia
- Concentrazione della produzione
- 25
- Rischio relativo di approvvigionamento
- 7
- Distribuzione delle riserve
- 54
- Stabilità politica (principale produttore)
- 48
- Stabilità politica (principale detentore di riserve)
- 48
Transizioni di fase e allotropi
| Punto di fusione | 3290,15 K |
| Punto di ebollizione | 5728,15 K |
Categorie degli stati di ossidazione
Dati di riferimento avanzati
Costanti di schermaggio (14)
| n | Orbitale | σ |
|---|---|---|
| 1 | s | 1,4163 |
| 2 | p | 4,4136 |
| 2 | s | 19,0702 |
| 3 | d | 13,5589 |
| 3 | p | 21,1996 |
| 3 | s | 21,9085 |
| 4 | d | 36,676 |
| 4 | f | 39,5296 |
| 4 | p | 34,2652 |
| 4 | s | 33,2412 |
Dettaglio dei raggi cristallini (5)
| Carica | CN | Spin | rcrystal (pm) | Origine |
|---|---|---|---|---|
| 3 | VI | 86 | estimated, | |
| 4 | VI | 82 | estimated, | |
| 5 | VI | 78 | ||
| 5 | VII | 83 | ||
| 5 | VIII | 88 |
Modalità di decadimento degli isotopi (52)
| Isotopo | Modalità | Intensità |
|---|---|---|
| 155 | p | 100% |
| 156 | p | 71% |
| 156 | B+ | 29% |
| 157 | A | 96,6% |
| 157 | p | 3,4% |
| 157 | B+ | — |
| 158 | A | 100% |
| 158 | B+ | — |
| 159 | B+ | 66% |
| 159 | A | 34% |
Fattori di diffusione dei raggi X (716)
| Energia (eV) | f₁ | f₂ |
|---|---|---|
| 10 | — | 3,16064 |
| 10,1152 | — | 3,23709 |
| 10,2317 | — | 3,31539 |
| 10,3496 | — | 3,39558 |
| 10,4688 | — | 3,47772 |
| 10,5894 | — | 3,56683 |
| 10,7114 | — | 3,65875 |
| 10,8348 | — | 3,75304 |
| 10,9596 | — | 3,84976 |
| 11,0859 | — | 3,94897 |
Dati aggiuntivi
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
2.0 milligrams per kilogram
Riferimenti (1)
- [5] Tantalum https://education.jlab.org/itselemental/ele073.html
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
2×10-6 milligrams per liter
Riferimenti (1)
- [5] Tantalum https://education.jlab.org/itselemental/ele073.html
Sources
Sources of this element.
Tantalum ores are found in Australia, Brazil, Mozambique, Thailand, Portugal, Nigeria, Zaire, and Canada.
Riferimenti (1)
- [6] Tantalum https://periodic.lanl.gov/73.shtml
Production
Production of this element (from raw materials or other compounds containing the element).
Separation of tantalum from niobium requires several complicated steps. Several methods are used to commercially produce the element, including electrolysis of molten potassium fluorotantalate, reduction of potassium fluorotantalate with sodium, or reacting tantalum carbide with tantalum oxide. Twenty five isotopes of tantalum are known to exist. Natural tantalum contains two isotopes.
Riferimenti (1)
- [6] Tantalum https://periodic.lanl.gov/73.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 Tantalum.
The element property data was retrieved from publications.