Thorium (Th)
actinideSolid
Peso atomico standard
232,0377 uConfigurazione elettronica
[Rn] 7s2 6d2Punto di fusione
1749,85 °CPunto di ebollizione
4787,85 °CDensità
1,172e+4 kg/m³Stati di ossidazione
−1, +1, +2, +3, +4Elettronegatività (Pauling)
1,3Energia di ionizzazione (1ª)
6,3067 eVAnno della scoperta
1828Raggio atomico
180 pmDettagli
Thorium is a naturally occurring actinide metal with atomic number 90. It is weakly radioactive and is found mainly as ²³²Th, an isotope with a very long half-life. Chemically it is dominated by the +4 oxidation state and often resembles the tetravalent lanthanides more than uranium or plutonium. Its main technological interest is as a fertile nuclear material that can be converted to fissile ²³³U in reactors.
When pure, thorium is a silvery-white metal that is air-stable and retains its luster for several months. When contaminated with the oxide, thorium slowly tarnishes in air, becoming gray and finally black. The physical properties of thorium are greatly influenced by the degree of contamination with the oxide. The purest specimens often contain several tenths of a percent of the oxide. High-purity thorium has been made. Pure thorium is soft, very ductile, and can be cold-rolled, swaged, and drawn. Thorium is dimorphic, changing at 1400°C from a cubic to a body-centered cubic structure. Thorium oxide has a melting point of 3300°C, which is the highest of all oxides. Only a few elements, such as tungsten, and a few compounds, such as tantalum carbide, have higher melting points. Thorium is slowly attacked by water, but does not dissolve readily in most common acids, except hydrochloric. Powdered thorium metal is often pyrophoric and should be handled carefully. When heated in air, thorium turnings ignite and burn brilliantly with a white light.
The name derives from Thor, the Scandinavian god of thunder. It was discovered in the mineral thorite (ThSiO4) by the Swedish chemist Jöns Jacob Berzelius in 1828. Thorium was first isolated by the chemists D. Lely, Jr. and L. Hamburger in 1914.
Thorium was discovered by Jöns Jacob Berzelius, a Swedish chemist, in 1828. He discovered it in a sample of a mineral that was given to him by the Reverend Has Morten Thrane Esmark, who suspected that it contained an unknown substance. Esmark's mineral is now known as thorite (ThSiO4). Thorium makes up about 0.0007% of the earth's crust and is primarily obtained from thorite, thorianite (ThO2) and monazite ((Ce, La, Th, Nd, Y)PO4).
Morten Esmark found a black mineral on Løvøya island, Norway and gave a sample to his father Jens Esmark, a noted mineralogist. The elder Esmark was not able to identify it and sent a sample to Swedish chemist Jöns Jakob Berzelius for examination in 1828. In 1829 Berzelius determined that it contained a new element, which he named thorium after Thor, the Norse god of thunder. The metal had no practical uses until 1885 when Carl Auer von Welsbach invented the gas mantle. Thorium was first observed to be radioactive in 1898, independently, by Polish-French physicist Marie Curie and German chemist Gerhard Carl Schmidt. Between 1900 and 1903, Ernest Rutherford and Frederick Soddy showed how thorium decayed at a fixed rate over time into a series of other elements. This observation led to the identification of half-life as one of the outcomes of the alpha particle experiments that led to their disintegration theory of radioactivity. The crystal bar process (or "iodide process") was discovered by Anton Eduard van Arkel and Jan Hendrik de Boer in 1925 to produce high-purity metallic thorium. Because of health concerns, the thorium in classic lantern mantles has been replaced by rare-earth elements that also produce intense light without the radioactivity.
Pure thorium is a silvery, soft, ductile metal when freshly prepared. It tarnishes slowly in air, forming a protective oxide film, and finely divided material can be more reactive. Macroscopic metal is uncommon outside specialized laboratories and nuclear materials work.
Thorium dioxide has been used in high-temperature ceramics, laboratory crucibles, optical glass, and older incandescent gas mantles, although most such uses have declined because of radioactivity controls. Small additions of thorium to tungsten improved electron emission in thoriated welding electrodes and some vacuum-tube components. Thorium is also studied as a fertile fuel material in nuclear systems, but it is not a widely deployed commercial reactor fuel.
Thorium is used as an alloying agent to improve magnesium's strength at high temperatures. Thorium is also used to coat tungsten filaments used in electronic devices, such at television sets. When bombarded with neutrons, thorium-232 becomes thorium-233, which eventually decays into uranium-233 through a series of beta decays. Uranium-233 is a fissionable material and can be used as a nuclear fuel.
Thorium oxide (ThO2), one of thorium's compounds, has many uses. It is primarily used in a type of lantern mantel known as a Welsbach mantle. This mantle, which also contains about 1% cerium oxide, glows with a bright white light when it is heated in a gas flame. Thorium oxide has a very high melting point, about 3300°C, and is used to make high temperature crucibles. Thorium oxide is also used to make glass with a high index of refraction that is used to make high quality camera lenses. Thorium oxide is used as a catalyst in the production of sulfuric acid (H2SO4), in the cracking of petroleum products and in the conversion of ammonia (NH3) to nitric acid (HNO3).
Thorium's most stable isotope, thorium-232, has a half-life of about 14,050,000,000 years. It decays into radium-228 through alpha decay or decays through spontaneous fission.
The principal historic use of thorium has been in the preparation of the Welsbach mantle, used for portable gaslights. These mantles, consisting of thorium oxide with about 1% cerium oxide and other ingredients, glow with a dazzling light when heated in a gas flame. Thorium is an important alloying element in magnesium, imparting high strength and creep resistance at elevated temperatures. Because thorium has a low work-function and high electron emission, it is used to coat tungsten wire used in electronic equipment. The oxide is also used to control the grain size of tungsten used for electric lamps; it is also used for high-temperature laboratory crucibles. Glasses containing thorium oxide have a high refractive index and low dispersion. Consequently, they find application in high quality lenses for cameras and scientific instruments. Thorium oxide has also found use as a catalyst in the conversion of ammonia to nitric acid, in petroleum cracking, and in producing sulfuric acid. Thorium metal is a source of nuclear power. There is probably more energy available for use from thorium in the minerals of the earth's crust than from both uranium and fossil fuels. Any sizable demand from thorium as a nuclear fuel is still several years in the future. Work has been done in developing thorium cycle converter-reactor systems. Several prototypes, including the HTGR (high-temperature gas-cooled reactor) and MSRE (molten salt converter reactor experiment), have operated. While the HTGR reactors are efficient, they are not expected to become important commercially for many years because of certain operating difficulties.
Isotopes in Earth/Planetary Science
234Th (with a half-life of 24 days) has been used as a tracer for estimating the flux of organic carbon in the ocean (Fig. IUPAC.90.1) [589] B. Ghaleb. IOP Conf. Ser. Earth Environ. Sci.5, (2009)., [590] J. K. Cochran, K. O. Buesseler, M. P. Bacon, H. W. Wang, D. J. Hirschberg, L. Ball, J. Andrews, G. Crossin, A. Fleer. Deep-Sea Res. II47, 3451 (2000).. 234Th has been used for estimating the residence time of suspended particulate matter (SPM) in water columns [589] B. Ghaleb. IOP Conf. Ser. Earth Environ. Sci.5, (2009)..
Isotopes in Geochronology
The decay of 232Th (with a half-life of 1.40×1010 years) to 208Pb is used to date rocks based on the accumulation of the stable daughter product 208Pb. The half-lives of the isotopes between the parent radionuclide 232Th and stable endpoint 208Pb all have much shorter half-lives than thorium. Therefore, the amount of 208Pb that accumulates in a sample is determined primarily by the amount of 232Th parent radionuclide present when the mineral was formed and the time that has elapsed since the mineral solidified [591] R. R. Parrish, S. R. Noble. Rev. Mineral. Geochem.53, 183 (2003)..
Another dating method, the 230Th/ 234U method, is based on the hypothesis that the sample contains uranium, but no 230Th at the time of its formation. Then, the age of the specimen is determined mainly by the amount of 230Th in the specimen. Reliable ages with this method range from several thousand to approximately 350 thousand years [292] M. A. Geyh, H. Schleicher. Absolute Age Determination: Physical and Chemical Dating Methods and Their Application, p. 503, Springer-Verlag, Berlin (1990)..
Isotopes in Industry
The most precise time and frequency measurements are performed with optical atomic clocks that use as a frequency standard the optical frequency generated as electrons change energy levels. It has been proposed that a nuclear clock, using a nuclear transition could outperform an electron transition. 229mTh, with a half-life of 13.9 h, has been confirmed as a possible candidate for a nuclear clock [592] L. von der Wense, B. Seiferle, M. Laatiaoui, J. B. Neumayr, H. J. Maier, H. F. Wirth, C. Mokry, J. Runke, K. Eberhardt, C. E. Düllmann, N. G. Trautmann, P. G. Thirolf. Nature533, 47 (2016).. The m in 229mTh indicates a metastable state of the isotope. The further development of a nuclear frequency standard will require more precise determinations of the energy and half-life of the isomer.
Thorium chemistry is strongly centered on Th⁴⁺. Thorium dioxide, ThO₂, is a very refractory oxide with high melting point and low solubility, important in ceramics and nuclear fuel research. Thorium nitrate, Th(NO₃)₄, was historically used to impregnate gas mantles. Thorium tetrafluoride, ThF₄, and thorium tetrachloride, ThCl₄, are representative halides and intermediates in metal preparation or molten-salt chemistry. Lower oxidation states are uncommon and generally require strongly reducing conditions.
See more information at the Thorium compound page.
Thorium is an alpha-emitting radioactive element, and the hazard depends on isotope, chemical form, and route of exposure. External radiation from bulk ²³²Th is usually limited, but inhaled or ingested dust can deliver internal alpha dose, especially as decay products accumulate. Thorium compounds are also heavy-metal toxicants. Machining, powder handling, and legacy mantles or electrodes require controls for contamination and radioactive waste.
Thorium occurs naturally in trace to minor amounts in many rocks and soils, chiefly in resistant minerals such as monazite and thorite. Th⁴⁺ is relatively immobile under many surface conditions because it hydrolyzes strongly and binds to oxides, phosphates, and organic matter. Weathering tends to concentrate thorium in heavy-mineral sands and sediments rather than in groundwater. It has no known biological function.
Thorium is not traded as a major commodity metal. It is obtained mainly as a by-product or potential by-product of rare-earth and heavy-mineral processing, especially from monazite concentrates, where radioactivity can complicate handling and permitting. Demand is limited because many former applications have been replaced by nonradioactive materials. Nuclear-fuel interest has led to research stocks and pilot-scale processing, but no large, mature thorium fuel market exists. Recycling is mostly relevant to controlled industrial or nuclear materials rather than general commerce.
Thorium-232 is a primordial nuclide, having existed in its current form for over 4.5 billion years, a half-life is comparable to the age of the Universe and thus predating the formation of the Earth. Thorium was forged in the cores of dying stars through the r-process and scattered across the galaxy by supernovas. Thorium is found in small amounts in most rocks and soils. Soil commonly contains an average of around 6 parts per million (ppm) of thorium. Thorium occurs in several minerals including thorite (ThSiO4), thorianite (ThO2 + UO2) and monazite. Thorianite is a rare mineral and may contain up to about 12% thorium oxide. Monazite contains 2.5% thorium, allanite has 0.1 to 2% thorium and zircon can have up to 0.4% thorium.[66] Thorium-containing minerals occur on all continents. Thorium is now thought to be about three times as abundant as uranium and about as abundant as lead or molybdenum. Thorium is recovered commercially from the mineral monazite, which contains from 3 to 9% ThO2 along with rare-earth minerals.
Thorium is produced in the rapid neutron-capture process and is one of the longest-lived naturally occurring radioactive elements heavier than bismuth. Its abundance in the Solar System is low, but it is measurable in meteorites, lunar samples, and stellar spectra. Ratios involving thorium and other r-process elements are used in cosmochronology because ²³²Th decays on a timescale comparable to the age of the universe.
- Nearly all natural thorium is ²³²Th, with a half-life of about 14 billion years.
- Thorium dioxide, ThO₂, is among the most refractory known oxides.
- Old gas mantles could contain enough thorium to be measurably radioactive.
- Thorium metal powder can present both radiological and pyrophoric hazards.
- The thorium fuel cycle breeds fissile ²³³U rather than using thorium itself as a fissile nuclide.
Immagini
Proprietà
Fisiche
- Raggio atomico (empirico)
- 180 pm Confronta Raggio atomico (empirico) di tutti gli elementi →
- Raggio covalente
- 206 pm Confronta Raggio covalente di tutti gli elementi →
- Raggio di van der Waals
- 237 pm Confronta Raggio di van der Waals di tutti gli elementi →
- Densità
- 1,172 × 104 kg/m³ Confronta Densità di tutti gli elementi →
- Volume molare
- 0,0198 L/mol
- Fase in condizioni STP
- Solido Confronta Fase in condizioni STP di tutti gli elementi →
- Punto di fusione
- 1749,85 °C Confronta Punto di fusione di tutti gli elementi →
- Punto di ebollizione
- 4787,85 °C Confronta Punto di ebollizione di tutti gli elementi →
- Capacità termica specifica
- 0,118 J/(g·K) Confronta Capacità termica specifica di tutti gli elementi →
- Capacità termica molare
- 27,32 J/(mol·K) Confronta Capacità termica molare di tutti gli elementi →
- Struttura cristallina
- Cubica a facce centrate Confronta Struttura cristallina di tutti gli elementi →
Chimiche
- Elettronegatività (Pauling)
- 1,3 Confronta Elettronegatività (Pauling) di tutti gli elementi →
- Affinità elettronica
- 0,607 eV
- Energia di ionizzazione (1ª)
- 6,3067 eV Confronta Energia di ionizzazione (1ª) di tutti gli elementi →
- Energia di ionizzazione (2ª)
- 12,100042 eV Confronta Energia di ionizzazione (2ª) di tutti gli elementi →
- Energia di ionizzazione (3ª)
- 18,320063 eV Confronta Energia di ionizzazione (3ª) di tutti gli elementi →
- Energia di ionizzazione (4ª)
- 28,648099 eV Confronta Energia di ionizzazione (4ª) di tutti gli elementi →
- Energia di ionizzazione (5ª)
- 58,0002 eV Confronta Energia di ionizzazione (5ª) di tutti gli elementi →
- Stati di ossidazione
- −1, +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
- [Rn] 7s2 6d2
Termodinamiche
- Calore di fusione
- 0,16696896 eV Confronta Calore di fusione di tutti gli elementi →
- Calore di vaporizzazione
- 5,327253 eV Confronta Calore di vaporizzazione di tutti gli elementi →
- Calore di sublimazione
- 5,938747 eV
- Calore di atomizzazione
- 5,938747 eV
- Entalpia di atomizzazione
- 6,239312 eV
Nucleari
- Protoni
- 90 Confronta Protoni di tutti gli elementi →
- Neutroni
- 142 Confronta Neutroni di tutti gli elementi →
- Isotopi noti
- 32 Confronta Isotopi noti di tutti gli elementi →
- Isotopi stabili
- 0 Confronta Isotopi stabili di tutti gli elementi →
- Isotopo più stabile
- Th-232
- Anno della scoperta
- 1828
Abbondanza
- Abbondanza (crosta terrestre)
- 9,6 mg/kg Confronta Abbondanza (crosta terrestre) di tutti gli elementi →
- Abbondanza (oceano)
- 1 × 10−6 mg/L Confronta Abbondanza (oceano) di tutti gli elementi →
Struttura cristallina
- Costante reticolare a
- 508 pm
Struttura elettronica
- Elettroni per guscio
- 2, 8, 18, 32, 18, 10, 2 Confronta Elettroni per guscio di tutti gli elementi →
Identificativi
- Numero CAS
- 7440-29-1 Confronta Numero CAS di tutti gli elementi →
- Simbolo di termine
- 3F2
- InChI
- InChI=1S/Th
- Chiave InChI
- ZSLUVFAKFWKJRC-UHFFFAOYSA-N
Configurazione elettronica Misurato
Th: 6d² 7s²[Rn] 6d² 7s²1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d¹⁰ 6s² 6p⁶ 6d² 7s²Modello 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
Nessun isotopo stabile.
| Numero di massa | Massa atomica (u) | Abbondanza naturale | Emivita |
|---|---|---|---|
| 223 Radioattivo | 223,0208119 ± 0,0000099 | N/D | 600 ms |
| 217 Radioattivo | 217,013117 ± 0,000022 | N/D | 248 us |
| 213 Radioattivo | 213,013009 ± 0,000076 | N/D | 144 ms |
| 218 Radioattivo | 218,013276 ± 0,000011 | N/D | 122 ns |
| 214 Radioattivo | 214,0115 ± 0,000017 | N/D | 87 ms |
Fase / Stato
Motivo: 1724,8 °C sotto il punto di fusione (1749,85 °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 90. Ordinamento per carica ionica crescente.
Righe disponibili ?
| Ione | Carica | Righe totali | Probabilità di transizione | Designazioni dei livelli |
|---|---|---|---|---|
| Th I | 0 | 13387 | 0 | 13387 |
| Th II | +1 | 6502 | 0 | 6502 |
| Th III | +2 | 227 | 0 | 227 |
| Th IV | +3 | 27 | 0 | 0 |
Livelli disponibili ?
| Ione | Carica | Livelli |
|---|---|---|
| Th I | 0 | 788 |
| Th II | +1 | 517 |
| Th III | +2 | 176 |
| Th IV | +3 | 2 |
| Th V | +4 | 2 |
| Th VI | +5 | 2 |
| Th VII | +6 | 2 |
| Th VIII | +7 | 2 |
| Th IX | +8 | 2 |
| Th X | +9 | 2 |
Raggi ionici
| Carica | Coordinazione | Spin | Raggio |
|---|---|---|---|
| +3 | 9 | N/D | 120.9 pm |
| +4 | 6 | N/D | 94 pm |
| +4 | 8 | N/D | 105 pm |
| +4 | 9 | N/D | 109.00000000000001 pm |
| +4 | 10 | N/D | 112.99999999999999 pm |
| +4 | 11 | N/D | 118 pm |
| +4 | 12 | N/D | 121 pm |
Composti
Isotopi (5)
Twenty-seven thorium radioisotopes have been characterized, with a range in atomic weight from 210 to 236. All are unstable with the most stable being 232Th with a half-life of 14.05 billion years. Thorium-232 represents all but a trace of naturally occurring thorium. It is an alpha emitter and goes through six alpha and four beta decay steps before becoming the stable isotope 208Pb. 232Th is sufficiently radioactive to expose a photographic plate in a few hours. Other isotopes of thorium are short-lived intermediates in the decay chains of higher elements, and only found in trace amounts. The longer-lived of these trace isotopes include: 230Th with a half-life of 75,380 years which is a daughter product of 238U decay; 229Th with a half-life of 7340 years and 228Th with a half-life of 1.92 years. All of the remaining radioactive isotopes have half-lives that are less than thirty days and the majority of these have half-lives less than ten minutes. Much of the internal heat the earth produces has been attributed to thorium and uranium.
| Numero di massa | Massa atomica (u) | Abbondanza naturale | Emivita | Modalità di decadimento | |
|---|---|---|---|---|---|
| 223 Radioattivo | 223,0208119 ± 0,0000099 | N/D | 600 ms | α =100% | |
| 217 Radioattivo | 217,013117 ± 0,000022 | N/D | 248 us | α =100% | |
| 213 Radioattivo | 213,013009 ± 0,000076 | N/D | 144 ms | α ≈100%β+ ? | |
| 218 Radioattivo | 218,013276 ± 0,000011 | N/D | 122 ns | α =100% | |
| 214 Radioattivo | 214,0115 ± 0,000017 | N/D | 87 ms | α ≈100%β+ ? |
Righe spettrali
Sono visualizzati 50 di 9955. Per impostazione predefinita sono mostrate soltanto le righe spettrali con intensità misurata.
| Lunghezza d'onda (nm) | Intensità | Stadio di ionizzazione | Tipo | Transizione | Accuratezza | Fonte | |
|---|---|---|---|---|---|---|---|
| 576.055056 nm | 53000 | Th I | emission | 6d2.7s2 3F → 5f.6d.7s2 3D* | Misurata | NIST | |
| 645.728238 nm | 44000 | Th I | emission | 5f.6d.7s2 3H* → 5f.6d.7s.7p 5I | Misurata | NIST | |
| 395.039509 nm | 42000 | Th I | emission | 6d2.7s2 3F → * | Misurata | NIST | |
| 618.262159 nm | 38000 | Th I | emission | 6d2.7s2 3F → 6d.7s2.7p 3P* | Misurata | NIST | |
| 658.390575 nm | 32000 | Th I | emission | 6d2.7s2 3F → 6d.7s2.7p 3F* | Misurata | NIST | |
| 572.018265 nm | 31000 | Th I | emission | 6d2.7s2 → 5f.6d.7s2 3D* | Misurata | NIST | |
| 698.965521 nm | 31000 | Th I | emission | 5f.6d.7s2 3H* → 5f.6d.7s.7p 5I | Misurata | NIST | |
| 716.889496 nm | 30000 | Th I | emission | 6d2.7s2 3F → 6d.7s2.7p 3F* | Misurata | NIST | |
| 449.3333668 nm | 28000 | Th I | emission | 6d2.7s2 3F → * | Misurata | NIST | |
| 658.853947 nm | 26000 | Th I | emission | 6d2.7s2 3P → 6d.7s2.7p 3P* | Misurata | NIST | |
| 691.12262 nm | 25000 | Th I | emission | 6d2.7s2 3F → 6d2.7s.7p 5G* | Misurata | NIST | |
| 380.307494 nm | 24000 | Th I | emission | 6d2.7s2 3F → 6d2.7s.7p 3D* | Misurata | NIST | |
| 403.6047645 nm | 24000 | Th I | emission | 6d2.7s2 3F → * | Misurata | NIST | |
| 659.148431 nm | 21000 | Th I | emission | 6d2.7s2 3F → 6d2.7s.7p 5G* | Misurata | NIST | |
| 401.912876 nm | 20000 | Th II | emission | 6d.7s2 2D → 6d.7s.(3D).7p * | Misurata | NIST | |
| 558.702644 nm | 20000 | Th I | emission | 6d2.7s2 3F → * | Misurata | NIST | |
| 411.2754309 nm | 18000 | Th I | emission | 6d2.7s2 3F → * | Misurata | NIST | |
| 470.398977 nm | 18000 | Th I | emission | 6d2.7s2 3F → * | Misurata | NIST | |
| 580.414105 nm | 18000 | Th I | emission | 6d2.7s2 3F → 6d2.7s.7p 5F* | Misurata | NIST | |
| 616.982198 nm | 18000 | Th I | emission | 6d2.7s2 3F → 5f.6d.7s2 3D* | Misurata | NIST | |
| 597.366467 nm | 17000 | Th I | emission | 6d2.7s2 → 6d.7s2.7p 3P* | Misurata | NIST | |
| 653.134169 nm | 17000 | Th I | emission | 6d3.(4F).7s 5F → 6d2.7s.7p 5P* | Misurata | NIST | |
| 383.969505 nm | 16000 | Th I | emission | 6d2.7s2 3F → * | Misurata | NIST | |
| 421.092303 nm | 16000 | Th I | emission | 6d2.7s2 3F → * | Misurata | NIST | |
| 515.86042 nm | 16000 | Th I | emission | 6d2.7s2 3F → * | Misurata | NIST | |
| 620.349239 nm | 16000 | Th I | emission | 6d2.7s2 3F → 6d2.7s.7p 5F* | Misurata | NIST | |
| 666.22685 nm | 16000 | Th I | emission | 6d3.(4F).7s 5F → 6d2.7s.7p 5P* | Misurata | NIST | |
| 394.8030341 nm | 15000 | Th I | emission | 6d2.7s2 3F → * | Misurata | NIST | |
| 403.0842224 nm | 15000 | Th I | emission | 6d2.7s2 3F → * | Misurata | NIST | |
| 410.0341193 nm | 15000 | Th I | emission | 6d2.7s2 3F → * | Misurata | NIST | |
| 467.366094 nm | 15000 | Th I | emission | 6d2.7s2 3F → * | Misurata | NIST | |
| 506.797381 nm | 15000 | Th I | emission | 5f.6d.7s2 3H* | Misurata | NIST | |
| 523.115956 nm | 15000 | Th I | emission | 6d2.7s2 3P → 6d2.7s.7p 5P* | Misurata | NIST | |
| 634.285945 nm | 15000 | Th I | emission | 6d3.(4F).7s 5F → * | Misurata | NIST | |
| 382.838452 nm | 14000 | Th I | emission | 6d2.7s2 3F → * | Misurata | NIST | |
| 472.3438197 nm | 14000 | Th I | emission | 6d2.7s2 3F → 5f.6d.7s2 3D* | Misurata | NIST | |
| 553.926178 nm | 14000 | Th I | emission | 6d3.(4F).7s 5F → * | Misurata | NIST | |
| 694.361046 nm | 14000 | Th I | emission | 6d3.(4F).7s 5F → * | Misurata | NIST | |
| 720.80062 nm | 14000 | Th I | emission | 6d3.(4F).7s 5F → * | Misurata | NIST | |
| 425.0314489 nm | 13000 | Th I | emission | 6d2.7s2 3F → * | Misurata | NIST | |
| 489.495493 nm | 13000 | Th I | emission | 6d2.7s2 3F → 6d.7s2.7p 3P* | Misurata | NIST | |
| 387.382217 nm | 12000 | Th I | emission | 6d2.7s2 3F → * | Misurata | NIST | |
| 423.5463454 nm | 12000 | Th I | emission | 6d2.7s2 3F → * | Misurata | NIST | |
| 480.81337 nm | 12000 | Th I | emission | 6d2.7s2 3F → * | Misurata | NIST | |
| 541.748576 nm | 12000 | Th I | emission | 6d2.7s2 → * | Misurata | NIST | |
| 599.412865 nm | 12000 | Th I | emission | 6d2.7s2 3P → 6d.7s2.7p 3P* | Misurata | NIST | |
| 659.393903 nm | 12000 | Th I | emission | 6d3.(4F).7s 5F → * | Misurata | NIST | |
| 708.416896 nm | 12000 | Th I | emission | 6d3.(4F).7s 5F → * | Misurata | NIST | |
| 738.550045 nm | 12000 | Th I | emission | 6d2.7s2 → 6d2.7s.7p 5F* | Misurata | NIST | |
| 392.440084 nm | 11000 | Th I | emission | 6d2.7s2 → * | Misurata | NIST |
Proprietà estese
Raggi covalenti (dati estesi)
- Raggio covalente (Pyykkö)
- 175 pm
- Raggio covalente (Pyykkö, legame doppio)
- 143 pm
- Raggio covalente (Pyykkö, legame triplo)
- 136 pm
Raggi di van der Waals
- Batsanov
- 240 pm
- Alvarez
- 293 pm
- UFF
- 339,6 pm
- MM3
- 274 pm
Raggi atomici e metallici
- Raggio atomico (Rahm)
- 288 pm
Scale di numerazione
- Mendeleev
- 16
- Pettifor
- 47
- Glawe
- 34
Scale di elettronegatività
- Ghosh
- 0
- Miedema
- 3
Polarizzabilità e dispersione
- Polarizzabilità dipolare
- 217 a.u.
- Polarizzabilità dipolare (inc.)
- 54 a.u.
Parametri di Miedema
- Volume molare di Miedema
- 19,8 cm3/mol
- Densità elettronica di Miedema
- 2
Rischio di approvvigionamento ed economia
- Concentrazione della produzione
- 80
- Rischio relativo di approvvigionamento
- 8
- Distribuzione delle riserve
- 31
- Stabilità politica (principale produttore)
- 11
- Stabilità politica (principale detentore di riserve)
- 57
Transizioni di fase e allotropi
| Punto di fusione | 2023,15 K |
| Punto di ebollizione | 5058,15 K |
Categorie degli stati di ossidazione
Dati di riferimento avanzati
Dettaglio dei raggi cristallini (7)
| Carica | CN | Spin | rcrystal (pm) | Origine |
|---|---|---|---|---|
| 4 | VI | 108 | calculated, | |
| 4 | VIII | 119 | from r^3 vs V plots, calculated, | |
| 4 | IX | 123 | ||
| 4 | X | 127 | estimated, | |
| 4 | XI | 132 | calculated, | |
| 4 | XII | 135 | calculated, | |
| 3 | IX | — | 134,9 |
Modalità di decadimento degli isotopi (52)
| Isotopo | Modalità | Intensità |
|---|---|---|
| 208 | A | 100% |
| 209 | A | — |
| 209 | B+ | — |
| 210 | A | 100% |
| 210 | B+ | — |
| 211 | A | 100% |
| 211 | B+ | — |
| 212 | A | 100% |
| 212 | B+ | — |
| 213 | A | 100% |
Fattori di diffusione dei raggi X (516)
| Energia (eV) | f₁ | f₂ |
|---|---|---|
| 10 | — | 3,14769 |
| 10,1617 | — | 3,1007 |
| 10,3261 | — | 3,05442 |
| 10,4931 | — | 3,00883 |
| 10,6628 | — | 2,96392 |
| 10,8353 | — | 2,91968 |
| 11,0106 | — | 2,87611 |
| 11,1886 | — | 2,83318 |
| 11,3696 | — | 2,79089 |
| 11,5535 | — | 2,74024 |
Dati aggiuntivi
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
9.6 milligrams per kilogram
Riferimenti (1)
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
1×10-6 milligrams per liter
Riferimenti (1)
Sources
Sources of this element.
Thorium-232 is a primordial nuclide, having existed in its current form for over 4.5 billion years, a half-life is comparable to the age of the Universe and thus predating the formation of the Earth. Thorium was forged in the cores of dying stars through the r-process and scattered across the galaxy by supernovas. Thorium is found in small amounts in most rocks and soils. Soil commonly contains an average of around 6 parts per million (ppm) of thorium. Thorium occurs in several minerals including thorite (ThSiO4), thorianite (ThO2 + UO2) and monazite. Thorianite is a rare mineral and may contain up to about 12% thorium oxide. Monazite contains 2.5% thorium, allanite has 0.1 to 2% thorium and zircon can have up to 0.4% thorium.[66] Thorium-containing minerals occur on all continents. Thorium is now thought to be about three times as abundant as uranium and about as abundant as lead or molybdenum. Thorium is recovered commercially from the mineral monazite, which contains from 3 to 9% ThO2 along with rare-earth minerals.
Riferimenti (1)
- [6] Thorium https://periodic.lanl.gov/90.shtml
Production
Production of this element (from raw materials or other compounds containing the element).
Production
Several methods are available for producing thorium metal; it can be obtained by reducing thorium oxide with calcium, by electrolysis of anhydrous thorium chloride in a fused mixture of sodium and potassium chlorides, by calcium reduction of thorium tetrachloride mixed with anhydrous zinc chloride, and by reduction of thorium tetrachloride with an alkali metal.
Riferimenti (1)
- [6] Thorium https://periodic.lanl.gov/90.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 Thorium.
The element property data was retrieved from publications.