Tantalum (Ta)
transition-metalSolid
Standardatomgewicht
180,94788 uElektronenkonfiguration
[Xe] 6s2 4f14 5d3Schmelzpunkt
3016,85 °CSiedepunkt
5457,85 °CDichte
1,64e+4 kg/m³Oxidationszustände
−3, −1, 0, +1, +2, +3, +4, +5Elektronegativität (Pauling)
1,5Ionisierungsenergie (1.)
7,549571 eVEntdeckungsjahr
1802Atomradius
145 pmDetails
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.
Bilder
Eigenschaften
Physikalisch
- Atomradius (empirisch)
- 145 pm Vergleiche Atomradius (empirisch) aller Elemente →
- Kovalenzradius
- 170 pm Vergleiche Kovalenzradius aller Elemente →
- Van-der-Waals-Radius
- 217 pm Vergleiche Van-der-Waals-Radius aller Elemente →
- Metallradius
- 134 pm Vergleiche Metallradius aller Elemente →
- Dichte
- 1,64 × 104 kg/m³ Vergleiche Dichte aller Elemente →
- Molares Volumen
- 0,0109 L/mol
- Aggregatzustand bei Standardbedingungen
- Fest Vergleiche Aggregatzustand bei Standardbedingungen aller Elemente →
- Schmelzpunkt
- 3016,85 °C Vergleiche Schmelzpunkt aller Elemente →
- Siedepunkt
- 5457,85 °C Vergleiche Siedepunkt aller Elemente →
- Wärmeleitfähigkeit
- 57,5 W/(m·K) Vergleiche Wärmeleitfähigkeit aller Elemente →
- Spezifische Wärmekapazität
- 0,14 J/(g·K) Vergleiche Spezifische Wärmekapazität aller Elemente →
- Molare Wärmekapazität
- 25,36 J/(mol·K) Vergleiche Molare Wärmekapazität aller Elemente →
- Kristallstruktur
- Raumzentriert kubisch Vergleiche Kristallstruktur aller Elemente →
Chemisch
- Elektronegativität (Pauling)
- 1,5 Vergleiche Elektronegativität (Pauling) aller Elemente →
- Elektronegativität (Allen)
- 1,34
- Elektronenaffinität
- 0,322 eV
- Ionisierungsenergie (1.)
- 7,549571 eV Vergleiche Ionisierungsenergie (1.) aller Elemente →
- Ionisierungsenergie (2.)
- 16,200056 eV Vergleiche Ionisierungsenergie (2.) aller Elemente →
- Ionisierungsenergie (3.)
- 23,10008 eV Vergleiche Ionisierungsenergie (3.) aller Elemente →
- Ionisierungsenergie (4.)
- 35,00012 eV Vergleiche Ionisierungsenergie (4.) aller Elemente →
- Ionisierungsenergie (5.)
- 48,272166 eV Vergleiche Ionisierungsenergie (5.) aller Elemente →
- Oxidationszustände
- −3, −1, 0, +1, +2, +3, +4, +5 Vergleiche Oxidationszustände aller Elemente →
- Valenzelektronen
- 5 Vergleiche Valenzelektronen aller Elemente →
- Elektronenkonfiguration
- [Xe] 6s2 4f14 5d3
Thermodynamisch
- Schmelzwärme
- 0,37902265 eV Vergleiche Schmelzwärme aller Elemente →
- Verdampfungswärme
- 7,804322 eV Vergleiche Verdampfungswärme aller Elemente →
- Sublimationswärme
- 8,104887 eV
- Atomisierungswärme
- 8,104887 eV
- Atomisierungsenthalpie
- 8,104887 eV
Nuklear
- Protonen
- 73 Vergleiche Protonen aller Elemente →
- Neutronen
- 108 Vergleiche Neutronen aller Elemente →
- Bekannte Isotope
- 40 Vergleiche Bekannte Isotope aller Elemente →
- Stabile Isotope
- 1 Vergleiche Stabile Isotope aller Elemente →
- Stabilstes Isotop
- Ta-181
- Entdeckungsjahr
- 1802
Häufigkeit
- Häufigkeit (Erdkruste)
- 2 mg/kg Vergleiche Häufigkeit (Erdkruste) aller Elemente →
- Häufigkeit (Ozean)
- 2 × 10−6 mg/L Vergleiche Häufigkeit (Ozean) aller Elemente →
Kristallstruktur
- Gitterkonstante a
- 331 pm
Elektronische Struktur
- Elektronen pro Schale
- 2, 8, 18, 32, 11, 2 Vergleiche Elektronen pro Schale aller Elemente →
Identifikatoren
- CAS-Nummer
- 7440-25-7 Vergleiche CAS-Nummer aller Elemente →
- Termsymbol
- 4F3/2
- InChI
- InChI=1S/Ta
- InChI-Key
- GUVRBAGPIYLISA-UHFFFAOYSA-N
Elektronenkonfiguration Gemessen
Ta: 4f¹⁴ 5d³ 6s²[Xe] 4f¹⁴ 5d³ 6s²1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d³ 6s²Atommodell
Isotope ändern die Neutronenzahl, Masse und Stabilität — nicht die Elektronenkonfiguration eines neutralen Atoms.
Schematisches Atommodell, nicht maßstabsgetreu.
Atomarer Fingerabdruck
Emissions- / Absorptionsspektrum
Isotopenverteilung
| Massenzahl | Atommasse (u) | Natürliche Häufigkeit | Halbwertszeit |
|---|---|---|---|
| 181 Stabil | 180,9479958 ± 0,000002 | 99,9880% | Stabil |
Phase / Zustand
Grund: 2991,8 °C unter Schmelzpunkt (3016,85 °C)
Schematisch, nicht maßstabsgetreu
Phasenübergangspunkte
Übergangsenergien
Energie benötigt, um 1 mol am Schmelzpunkt zu schmelzen
Energie benötigt, um 1 mol am Siedepunkt zu verdampfen
Energie benötigt, um 1 mol am Sublimationspunkt zu sublimieren
Dichte
Bei Standardbedingungen
Bei Standardbedingungen
Atomspektren
10 von 73 angezeigt. Sortiert nach Ionenladung (aufsteigend).
Liniendaten ?
| Ion | Ladung | Gesamtlinien | Übergangswahrscheinlichkeiten | Niveau-Bezeichnungen |
|---|---|---|---|---|
| Ta I | 0 | 526 | 200 | 510 |
| Ta II | +1 | 141 | 0 | 13 |
| Ta IV | +3 | 83 | 0 | 0 |
| Ta V | +4 | 12 | 0 | 0 |
Niveaudaten ?
| Ion | Ladung | Niveaus |
|---|---|---|
| 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 |
Ionenradien
| Ladung | Koordination | Spin | Radius |
|---|---|---|---|
| +3 | 6 | N/A | 72 pm |
| +4 | 6 | N/A | 68 pm |
| +5 | 6 | N/A | 64 pm |
| +5 | 7 | N/A | 69 pm |
| +5 | 8 | N/A | 74 pm |
Verbindungen
Isotope (1)
| Massenzahl | Atommasse (u) | Natürliche Häufigkeit | Halbwertszeit | Zerfallsart | |
|---|---|---|---|---|---|
| 181 Stabil | 180,9479958 ± 0,000002 | 99,9880% ± 0,0003% | Stabil | stable |
Erweiterte Eigenschaften
Kovalente Radien (Erweitert)
- Kovalenzradius (Pyykkö)
- 146 pm
- Kovalenzradius (Pyykkö, doppelt)
- 126 pm
- Kovalenzradius (Pyykkö, dreifach)
- 119 pm
Van-der-Waals-Radien
- Batsanov
- 220 pm
- Alvarez
- 253 pm
- UFF
- 317 pm
- MM3
- 243 pm
Atom- & Metallische Radien
- Atomradius (Rahm)
- 258 pm
- Metallradius (C12)
- 146 pm
Nummerierungsskalen
- Mendeleev
- 49
- Pettifor
- 53
- Glawe
- 52
Elektronegativitätsskalen
- Ghosh
- 0
- Miedema
- 4
- Gunnarsson–Lundqvist
- 5
- Robles–Bartolotti
- 4
Polarisierbarkeit & Dispersion
- Dipolpolarisierbarkeit
- 74 a.u.
- Dipolpolarisierbarkeit (Uns.)
- 20 a.u.
- C₆ (Gould–Bučko)
- 887 Ha·Bohr6
Miedema-Parameter
- Miedema-Molvolumen
- 10,81 cm3/mol
- Miedema-Elektronendichte
- 4
Lieferrisiko & Wirtschaftlichkeit
- Produktionskonzentration
- 25
- Relatives Lieferrisiko
- 7
- Reservenverteilung
- 54
- Politische Stabilität (Top-Produzent)
- 48
- Politische Stabilität (Top-Reserven)
- 48
Phasenübergänge & Allotrope
| Schmelzpunkt | 3290,15 K |
| Siedepunkt | 5728,15 K |
Oxidationszustands-Kategorien
Erweiterte Referenzdaten
Abschirmkonstanten (14)
| n | Orbital | 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 |
Kristallradien-Details (5)
| Ladung | CN | Spin | rcrystal (pm) | Herkunft |
|---|---|---|---|---|
| 3 | VI | 86 | estimated, | |
| 4 | VI | 82 | estimated, | |
| 5 | VI | 78 | ||
| 5 | VII | 83 | ||
| 5 | VIII | 88 |
Isotopenzerfallsarten (52)
| Isotop | Modus | Intensität |
|---|---|---|
| 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% |
Röntgenstreufaktoren (716)
| Energie (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 |
Zusätzliche Daten
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
2.0 milligrams per kilogram
Referenzen (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
Referenzen (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.
Referenzen (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.
Referenzen (1)
- [6] Tantalum https://periodic.lanl.gov/73.shtml
Referenzen
(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.