Thallium (Tl)
post-transition-metalSolid
Peso atomico standard
204,38 u [204,382, 204,385]Configurazione elettronica
[Xe] 6s2 4f14 5d10 6p1Punto di fusione
303,85 °CPunto di ebollizione
1472,85 °CDensità
1,18e+4 kg/m³Stati di ossidazione
−5, −2, −1, +1, +2, +3Elettronegatività (Pauling)
1,62Energia di ionizzazione (1ª)
6,108287 eVAnno della scoperta
1861Raggio atomico
190 pmDettagli
Thallium is a soft post-transition metal in group 13. It is chemically notable for the stability of the +1 oxidation state, which reflects the inert-pair effect and makes many thallium(I) salts resemble alkali-metal salts in size and solubility behavior. The element is rare in ores and is usually recovered as a by-product of processing sulfide minerals. Its severe toxicity has greatly reduced former consumer and agricultural uses.
When freshly exposed to air, thallium exhibits a metallic luster, but soon develops a bluish-gray tinge, resembling lead in appearance. A heavy oxide builds up on thallium if left in air, and in the presence of water the hydride is formed. The metal is very soft and malleable. It can be cut with a knife. Twenty five isotopic forms of thallium, with atomic masses ranging from 184 to 210 are recognized. Natural thallium is a mixture of two isotopes. A mercury-thallium alloy, which forms a eutectic at 8.5% thallium, is reported to freeze at -60C, some 20 degrees below the freezing point of mercury.
The name derives from the Greek thallos for "green shoot" or "twig" because of the bright green line in its spectrum. Thallium was discovered by the English physicist and chemist William Crookes in 1861. Metallic thallium was first isolated by the French chemist Claude-Auguste Lamy in 1862.
Thallium was discovered spectroscopically by Sir William Crookes, an English chemist, in 1861. Crooks had obtained the sludge left over from the production of sulfuric acid (H2SO4) from a friend. After removing all of the selenium from the sludge, he inspected it with a device known as a spectroscope to look for signs of tellurium. Rather than seeing the yellow spectral lines produced by tellurium, he observed a bright green line that no one had ever seen before. He named the new element that was producing the green line thallium, after the greek word for 'green twig', thallos. He isolated samples of thallium the next year. Thallium is found in the minerals crooksite (CuThSe), lorandite (TlAsS2) and hutchinsonite ((Pb, Tl)2As5S9), but is usually obtained as a byproduct of the production of sulfuric acid or as a byproduct of refining zinc or lead.
From Greek thallos, meanin a green shoot or twig. Thallium was discovered spectroscopically in 1861 by Crookes. The element was named after the beautiful green spectral line, which identified the element. The metal was isolated both by Crookes and by Lamy in 1862 at about the same time.
Pure thallium is a very soft, heavy metal with a fresh silvery luster. It tarnishes readily in air, developing a dull gray oxide coating. It is malleable enough to be cut with a knife and has a relatively low melting point for a metal.
Current uses are limited by toxicity and regulation. Thallium is used in some specialty infrared optical materials, low-melting glasses, and semiconductor or detector research. Thallium-201 is an important medical radioisotope for diagnostic imaging of cardiac perfusion. Historical uses included rodenticides, insecticides, and depilatory agents, but these were abandoned or tightly restricted in many countries because of poisoning risks.
There are no uses for metallic thallium since pure thallium quickly combines with oxygen and water vapor from the atmosphere, forming a black, powdery substance. Thallium, used in conjunction with sulfur or selenium and arsenic, forms low melting glass. Thallium sulfate (Tl2SO4), an odorless, tasteless thallium compound, was once used as a rat and ant poison, although it has been banned from household use in the United States since 1974. Thallium sulfide (Tl2S), thallium iodide (TlI) and thallium bromide (TlBr) are all compounds used in devices to detect infrared radiation.
Thallium sulfate has been widely employed as a rodenticide and ant killer. It is odorless and tasteless, giving no warning of its presence. Its use, however, has been prohibited in the U.S. since 1975 as a household insecticide and rodenticide. The electrical conductivity of thallium sulfide changes with exposure to infrared light, and this compound is used in photocells. Thallium bromide-iodide crystals have been used as infrared optical materials. Thallium has been used, with sulfur or selenium and arsenic, to produce low melting glasses with become fluid between 125 and 150C. These glasses have properties at room temperatures similar to ordinary glasses and are said to be durable and insoluble in water. Thallium oxide has been used to produce glasses with a high index of refraction, and is used in the manufacture of photo cells. Thallium has been used in treating ringworm and other skin infections; however, its use has been limited because of the narrow margin between toxicity and therapeutic benefits.
Isotopes in Earth/Planetary Science
Because molecules, atoms, and ions of the stable isotopes of thallium possess slightly different physical and chemical properties, they commonly will be fractionated during physical, chemical, and biological processes, giving rise to variations in isotopic abundances and in atomic weights. There are substantial variations in the isotopic abundances of thallium in natural terrestrial materials (Fig. IUPAC.81.1). These variations are useful in investigating the origin of substances and studying environmental, hydrological, and geological processes [538] M. Rehkamper, M. Frank, J. R. Hein, D. Porcelli, A. Halliday, J. Ingri, V. Liebetrau. Earth. Planet. Sci. Lett.197, 65 (2002).. The isotope-amount ratio n(205Tl)/n(203Tl) has been used to study how trace metals are transported and distributed in hydrothermal fluids [538] M. Rehkamper, M. Frank, J. R. Hein, D. Porcelli, A. Halliday, J. Ingri, V. Liebetrau. Earth. Planet. Sci. Lett.197, 65 (2002).. The n(205Tl)/n(203Tl) ratio has also been used to study the cycling, distribution, and behavior of thallium in the marine environment [538] M. Rehkamper, M. Frank, J. R. Hein, D. Porcelli, A. Halliday, J. Ingri, V. Liebetrau. Earth. Planet. Sci. Lett.197, 65 (2002)..
Isotopes in Medicine
201Tl scintigraphy is used to detect coronary artery disease [539] G. A. Beller, B. L. Zaret. Circulation101, 1465 (2000).. Imaging of 201Tl (with a half-life of 3 days), can be used for exercise perfusion tests of the myocardium (muscular tissue of the heart), which determine damage to the heart caused by a heart attack or by heart disease (Fig. IUPAC.81.2) [539] G. A. Beller, B. L. Zaret. Circulation101, 1465 (2000)..
Isotopes Used as a Source of Radioactive Isotope(s)
203Tl is used in the production of 201Tl via the 203Tl (p, 3 n) 201Pb reaction, which is followed by a subsequent electron capture decay reaction of 201Pb to finally yield 201Tl. 205Tl is used as an alternative target in the production of 201Tl.
Thallium chemistry is dominated by thallium(I), Tl⁺, and thallium(III), Tl³⁺, with Tl⁺ usually more stable in aqueous and many solid-state compounds. Representative thallium(I) compounds include thallium(I) sulfate, Tl₂SO₄, thallium(I) nitrate, TlNO₃, and thallium(I) chloride, TlCl. Thallium(III) oxide, Tl₂O₃, and thallium(III) chloride, TlCl₃, are stronger oxidizing or less stable species. Mixed thallium compounds occur in chalcogenide and halide materials used for optical and electronic studies.
See more information at the Thallium compound page.
Thallium and soluble thallium compounds are highly toxic by ingestion, inhalation, or skin exposure. Tl⁺ can interfere with potassium-dependent biological processes, and poisoning may have delayed neurological, gastrointestinal, and hair-loss symptoms. Dusts, fumes, and soluble salts are the main occupational hazards. Radioisotopes such as thallium-201 add external and internal radiation hazards that are isotope- and activity-dependent.
The element and its compounds are toxic and should be handled carefully. Contact of the metal with skin is dangerous, and when melting the metal adequate ventilation should be provided. Exposure to thallium (soluble compounds) - skin, as Tl, should not exceed 0.1 mg/m3 (8-hour time-weighted average - 40-hour work week). Thallium is suspected of carcinogenic potential for man.
Thallium occurs naturally at low concentrations, commonly associated with potassium minerals, sulfide ores, and some coals. Mining, smelting, cement production, and coal combustion can mobilize it locally. In the environment, Tl⁺ is relatively mobile in some waters and can be taken up by plants because of its chemical similarity to K⁺. It has no known beneficial biological role and can be a concern near contaminated industrial sites.
Thallium is not mined as a primary product. It is recovered mainly from flue dusts, residues, and by-product streams generated during refining of zinc, lead, copper, and other sulfide ores. Demand is small and specialized, with toxicity limiting broader applications and encouraging substitution. Supply can therefore depend more on base-metal processing practices, regulatory controls, and purification capacity than on dedicated thallium mining. Recycling is limited to particular industrial or research materials.
Thallium occurs in crooksite, lorandite, and hutchinsonite. It is also present in pyrites and is recovered from the roasting of this ore in connection with the production of sulfuric acid. It is also obtained from the smelting of lead and zinc ores. Extraction is somewhat complex and depends on the source of the thallium. Manganese nodules, found on the ocean floor, contain thallium.
Thallium is a heavy, rare element in cosmic terms. Its stable isotopes, ²⁰³Tl and ²⁰⁵Tl, are produced by neutron-capture processes in earlier generations of stars, with contributions from both slow and rapid neutron-capture pathways. It is not a major rock-forming element, but on planets it can concentrate in sulfide phases and volatile-rich geochemical reservoirs.
- Thallium was discovered by its bright green spectral line, which inspired its name from the Greek word for a green shoot
- Fresh thallium can be cut easily, but the exposed surface dulls quickly in air
- Tl⁺ is close enough in behavior to K⁺ to enter some biological potassium pathways
- Thallium(I) sulfate, Tl₂SO₄, was once used as a rodenticide before its toxicity led to severe restrictions
- Natural thallium consists chiefly of two stable isotopes, ²⁰³Tl and ²⁰⁵Tl
Immagini
Proprietà
Fisiche
- Raggio atomico (empirico)
- 190 pm Confronta Raggio atomico (empirico) di tutti gli elementi →
- Raggio covalente
- 145 pm Confronta Raggio covalente di tutti gli elementi →
- Raggio di van der Waals
- 196 pm Confronta Raggio di van der Waals di tutti gli elementi →
- Raggio metallico
- 144 pm Confronta Raggio metallico di tutti gli elementi →
- Densità
- 1,18 × 104 kg/m³ Confronta Densità di tutti gli elementi →
- Volume molare
- 0,0172 L/mol
- Fase in condizioni STP
- Solido Confronta Fase in condizioni STP di tutti gli elementi →
- Punto di fusione
- 303,85 °C Confronta Punto di fusione di tutti gli elementi →
- Punto di ebollizione
- 1472,85 °C Confronta Punto di ebollizione di tutti gli elementi →
- Conducibilità termica
- 46,1 W/(m·K) Confronta Conducibilità termica di tutti gli elementi →
- Capacità termica specifica
- 0,129 J/(g·K) Confronta Capacità termica specifica di tutti gli elementi →
- Capacità termica molare
- 26,32 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)
- 1,62 Confronta Elettronegatività (Pauling) di tutti gli elementi →
- Elettronegatività (Allen)
- 1,789
- Affinità elettronica
- 0,377 eV
- Energia di ionizzazione (1ª)
- 6,108287 eV Confronta Energia di ionizzazione (1ª) di tutti gli elementi →
- Energia di ionizzazione (2ª)
- 20,42837 eV Confronta Energia di ionizzazione (2ª) di tutti gli elementi →
- Energia di ionizzazione (3ª)
- 29,852103 eV Confronta Energia di ionizzazione (3ª) di tutti gli elementi →
- Energia di ionizzazione (4ª)
- 51,140176 eV Confronta Energia di ionizzazione (4ª) di tutti gli elementi →
- Energia di ionizzazione (5ª)
- 62,600215 eV Confronta Energia di ionizzazione (5ª) di tutti gli elementi →
- Stati di ossidazione
- −5, −2, −1, +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 4f14 5d10 6p1
Termodinamiche
- Calore di fusione
- 0,04290822 eV Confronta Calore di fusione di tutti gli elementi →
- Calore di vaporizzazione
- 1,71011 eV Confronta Calore di vaporizzazione di tutti gli elementi →
- Calore di sublimazione
- 1,888376 eV
- Calore di atomizzazione
- 1,888376 eV
- Entalpia di atomizzazione
- 1,888376 eV
Nucleari
- Protoni
- 81 Confronta Protoni di tutti gli elementi →
- Neutroni
- 124 Confronta Neutroni di tutti gli elementi →
- Isotopi noti
- 43 Confronta Isotopi noti di tutti gli elementi →
- Isotopi stabili
- 2 Confronta Isotopi stabili di tutti gli elementi →
- Isotopo più stabile
- Tl-205
- Anno della scoperta
- 1861
Abbondanza
- Abbondanza (crosta terrestre)
- 0,85 mg/kg Confronta Abbondanza (crosta terrestre) di tutti gli elementi →
- Abbondanza (oceano)
- 1,9 × 10−5 mg/L Confronta Abbondanza (oceano) di tutti gli elementi →
Struttura cristallina
- Costante reticolare a
- 346 pm
Struttura elettronica
- Elettroni per guscio
- 2, 8, 18, 32, 18, 3 Confronta Elettroni per guscio di tutti gli elementi →
Identificativi
- Numero CAS
- 7440-28-0 Confronta Numero CAS di tutti gli elementi →
- Simbolo di termine
- 2P°1/2
- InChI
- InChI=1S/Tl
- Chiave InChI
- BKVIYDNLLOSFOA-UHFFFAOYSA-N
Configurazione elettronica Misurato
Tl: 4f¹⁴ 5d¹⁰ 6s² 6p¹[Xe] 4f¹⁴ 5d¹⁰ 6s² 6p¹1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d¹⁰ 6s² 6p¹Modello 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 |
|---|---|---|---|
| 203 Stabile | 202,9723446 ± 0,0000014 | 29,5200% | Stabile |
| 205 Stabile | 204,9744278 ± 0,0000014 | 70,4800% | Stabile |
Fase / Stato
Motivo: 278,9 °C sotto il punto di fusione (303,85 °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 81. Ordinamento per carica ionica crescente.
Righe disponibili ?
| Ione | Carica | Righe totali | Probabilità di transizione | Designazioni dei livelli |
|---|---|---|---|---|
| Tl I | 0 | 65 | 25 | 11 |
| Tl II | +1 | 82 | 3 | 7 |
| Tl III | +2 | 22 | 0 | 0 |
| Tl IV | +3 | 35 | 0 | 0 |
Livelli disponibili ?
| Ione | Carica | Livelli |
|---|---|---|
| Tl I | 0 | 70 |
| Tl II | +1 | 82 |
| Tl III | +2 | 109 |
| Tl IV | +3 | 44 |
| Tl V | +4 | 2 |
| Tl VI | +5 | 2 |
| Tl VII | +6 | 2 |
| Tl VIII | +7 | 2 |
| Tl IX | +8 | 2 |
| Tl X | +9 | 2 |
Raggi ionici
| Carica | Coordinazione | Spin | Raggio |
|---|---|---|---|
| +1 | 6 | N/D | 150 pm |
| +1 | 8 | N/D | 159 pm |
| +1 | 12 | N/D | 170 pm |
| +3 | 4 | N/D | 75 pm |
| +3 | 6 | N/D | 88.5 pm |
| +3 | 8 | N/D | 98 pm |
Composti
Isotopi (2)
| Numero di massa | Massa atomica (u) | Abbondanza naturale | Emivita | Modalità di decadimento | |
|---|---|---|---|---|---|
| 203 Stabile | 202,9723446 ± 0,0000014 | 29,5200% ± 0,0100% | Stabile | stable | |
| 205 Stabile | 204,9744278 ± 0,0000014 | 70,4800% ± 0,0100% | Stabile | stable |
Proprietà estese
Raggi covalenti (dati estesi)
- Raggio covalente (Pyykkö)
- 144 pm
- Raggio covalente (Pyykkö, legame doppio)
- 142 pm
- Raggio covalente (Pyykkö, legame triplo)
- 150 pm
- Raggio covalente (Bragg)
- 190 pm
Raggi di van der Waals
- Bondi
- 196 pm
- Batsanov
- 220 pm
- Alvarez
- 247 pm
- UFF
- 434,7 pm
- MM3
- 259 pm
Raggi atomici e metallici
- Raggio atomico (Rahm)
- 242 pm
- Raggio metallico (C12)
- 160 pm
Scale di numerazione
- Mendeleev
- 85
- Pettifor
- 78
- Glawe
- 81
Scale di elettronegatività
- Ghosh
- 0
- Miedema
- 4
- Gunnarsson–Lundqvist
- 3
- Robles–Bartolotti
- 2
Polarizzabilità e dispersione
- Polarizzabilità dipolare
- 50 a.u.
- Polarizzabilità dipolare (inc.)
- 2 a.u.
- C₆ (Gould–Bučko)
- 509 Ha·Bohr6
Parametri di Miedema
- Volume molare di Miedema
- 17,23 cm3/mol
- Densità elettronica di Miedema
- 1
Transizioni di fase e allotropi
| Punto di fusione | 577,15 K |
| Punto di ebollizione | 1746,15 K |
Categorie degli stati di ossidazione
Dati di riferimento avanzati
Costanti di schermaggio (15)
| n | Orbitale | σ |
|---|---|---|
| 1 | s | 1,5591 |
| 2 | p | 4,5138 |
| 2 | s | 21,3158 |
| 3 | d | 13,4658 |
| 3 | p | 22,6335 |
| 3 | s | 23,5809 |
| 4 | d | 37,6112 |
| 4 | f | 38,1324 |
| 4 | p | 35,7832 |
| 4 | s | 34,9212 |
Dettaglio dei raggi cristallini (6)
| Carica | CN | Spin | rcrystal (pm) | Origine |
|---|---|---|---|---|
| 1 | VI | 164 | from r^3 vs V plots, | |
| 1 | VIII | 173 | from r^3 vs V plots, | |
| 1 | XII | 184 | from r^3 vs V plots, estimated, | |
| 3 | IV | 89 | ||
| 3 | VI | 102,5 | from r^3 vs V plots, | |
| 3 | VIII | 112 | calculated, |
Modalità di decadimento degli isotopi (69)
| Isotopo | Modalità | Intensità |
|---|---|---|
| 176 | p | 100% |
| 176 | A | — |
| 176 | B+ | — |
| 177 | A | 73% |
| 177 | p | — |
| 178 | A | 62% |
| 178 | B+ | 38% |
| 178 | B+SF | 0,1% |
| 179 | A | 60% |
| 179 | B+ | — |
Fattori di diffusione dei raggi X (516)
| Energia (eV) | f₁ | f₂ |
|---|---|---|
| 10 | — | 1,80392 |
| 10,1617 | — | 1,75555 |
| 10,3261 | — | 1,69589 |
| 10,4931 | — | 1,59546 |
| 10,6628 | — | 1,46625 |
| 10,8353 | — | 1,39341 |
| 11,0106 | — | 1,31349 |
| 11,1886 | — | 1,20783 |
| 11,3696 | — | 1,13261 |
| 11,5535 | — | 1,07387 |
Dati aggiuntivi
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
8.5×10-1 milligrams per kilogram
Riferimenti (1)
- [5] Thallium https://education.jlab.org/itselemental/ele081.html
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
1.9×10-5 milligrams per liter
Riferimenti (1)
- [5] Thallium https://education.jlab.org/itselemental/ele081.html
Sources
Sources of this element.
Thallium occurs in crooksite, lorandite, and hutchinsonite. It is also present in pyrites and is recovered from the roasting of this ore in connection with the production of sulfuric acid. It is also obtained from the smelting of lead and zinc ores. Extraction is somewhat complex and depends on the source of the thallium. Manganese nodules, found on the ocean floor, contain thallium.
Riferimenti (1)
- [6] Thallium https://periodic.lanl.gov/81.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.
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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 Thallium.
The element property data was retrieved from publications.