Thallium

Last updated
Thallium, 81Tl
Thallium pieces in ampoule.jpg
Thallium
Pronunciation /ˈθæliəm/ ​(THAL-ee-əm)
Appearancesilvery white
Standard atomic weight Ar°(Tl)
Thallium in the periodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson
In
↑
Tl
↓
Nh
mercury ← thallium → lead
Atomic number (Z)81
Group group 13 (boron group)
Period period 6
Block   p-block
Electron configuration [ Xe ] 4f14 5d10 6s2 6p1
Electrons per shell2, 8, 18, 32, 18, 3
Physical properties
Phase at  STP solid
Melting point 577  K ​(304 °C,​579 °F)
Boiling point 1746 K​(1473 °C,​2683 °F)
Density (at 20° C)11.873 g/cm3  [3]
when liquid (at  m.p.)11.22 g/cm3
Heat of fusion 4.14  kJ/mol
Heat of vaporization 165 kJ/mol
Molar heat capacity 26.32 J/(mol·K)
Vapor pressure
P (Pa)1101001 k10 k100 k
at T (K)8829771097125214611758
Atomic properties
Oxidation states −5, [4] −2, −1, +1, +2, +3 (a mildly basic oxide)
Electronegativity Pauling scale: 1.62
Ionization energies
  • 1st: 589.4 kJ/mol
  • 2nd: 1971 kJ/mol
  • 3rd: 2878 kJ/mol
Atomic radius empirical:170  pm
Covalent radius 145±7 pm
Van der Waals radius 196 pm
Thallium spectrum visible.png
Spectral lines of thallium
Other properties
Natural occurrence primordial
Crystal structure ​ hexagonal close-packed (hcp)(hP2)
Lattice constants
Hexagonal close packed.svg
a = 345.66 pm
c = 552.52 pm (at 20 °C) [3]
Thermal expansion 29.9 µm/(m⋅K)(at 25 °C)
Thermal conductivity 46.1 W/(m⋅K)
Electrical resistivity 0.18 µΩ⋅m(at 20 °C)
Magnetic ordering diamagnetic [5]
Molar magnetic susceptibility −50.9×10−6 cm3/mol(298 K) [6]
Young's modulus 8 GPa
Shear modulus 2.8 GPa
Bulk modulus 43 GPa
Speed of sound thin rod818 m/s(at 20 °C)
Poisson ratio 0.45
Mohs hardness 1.2
Brinell hardness 26.5–44.7 MPa
CAS Number 7440-28-0
History
Namingafter Greek thallos, green shoot or twig
Discovery William Crookes (1861)
First isolation Claude-Auguste Lamy (1862)
Isotopes of thallium
Main isotopes [7] Decay
abun­dance half-life (t1/2) mode pro­duct
201Tl synth 3.0421 d ε 201Hg
203Tl29.5% stable
204Tlsynth3.78 y β− 204Pb
ε + β+ 204Hg
205Tl70.5%stable
Symbol category class.svg  Category: Thallium
| references

Thallium is a chemical element; it has symbol Tl and atomic number 81. It is a gray post-transition metal that is not found free in nature. When isolated, thallium resembles tin, but discolors when exposed to air. Chemists William Crookes and Claude-Auguste Lamy discovered thallium independently in 1861, in residues of sulfuric acid production. Both used the newly developed method of flame spectroscopy, in which thallium produces a notable green spectral line. Thallium, from Greek θαλλός, thallós , meaning "green shoot" or "twig", was named by Crookes. It was isolated by both Lamy and Crookes in 1862; Lamy by electrolysis, and Crookes by precipitation and melting of the resultant powder. Crookes exhibited it as a powder precipitated by zinc at the international exhibition, which opened on 1 May that year. [8]

Contents

Thallium tends to form the +3 and +1 oxidation states. The +3 state resembles that of the other elements in group 13 (boron, aluminium, gallium, indium). However, the +1 state, which is far more prominent in thallium than the elements above it, recalls the chemistry of alkali metals, and thallium(I) ions are found geologically mostly in potassium-based ores, and (when ingested) are handled in many ways like potassium ions (K+) by ion pumps in living cells.

Commercially, thallium is produced not from potassium ores, but as a byproduct from refining of heavy-metal sulfide ores. Approximately 65% of thallium production is used in the electronics industry, and the remainder is used in the pharmaceutical industry and in glass manufacturing. [9] It is also used in infrared detectors. The radioisotope thallium-201 (as the soluble chloride TlCl) is used in small amounts as an agent in a nuclear medicine scan, during one type of nuclear cardiac stress test.

Soluble thallium salts (many of which are nearly tasteless) are highly toxic, and they were historically used in rat poisons and insecticides. Because of their nonselective toxicity, use of these compounds has been restricted or banned in many countries. Thallium poisoning usually results in hair loss. Because of its historic popularity as a murder weapon, thallium has gained notoriety as "the poisoner's poison" and "inheritance powder" (alongside arsenic). [10]

Characteristics

A thallium atom has 81 electrons, arranged in the electron configuration [Xe]4f145d106s26p1; of these, the three outermost electrons in the sixth shell are valence electrons. Due to the inert pair effect, the 6s electron pair is relativistically stabilised and it is more difficult to get these involved in chemical bonding than it is for the heavier elements. Thus, very few electrons are available for metallic bonding, similar to the neighboring elements mercury and lead. Thallium, then, like its congeners, is a soft, highly electrically conducting metal with a low melting point, of 304 °C. [11]

A number of standard electrode potentials, depending on the reaction under study, [12] are reported for thallium, reflecting the greatly decreased stability of the +3 oxidation state: [11]

+0.73Tl3+ + 3 e−↔ Tl
−0.336Tl+ + e−↔ Tl

Thallium is the first element in group 13 where the reduction of the +3 oxidation state to the +1 oxidation state is spontaneous under standard conditions. [11] Since bond energies decrease down the group, with thallium, the energy released in forming two additional bonds and attaining the +3 state is not always enough to outweigh the energy needed to involve the 6s-electrons. [13] Accordingly, thallium(I) oxide and hydroxide are more basic and thallium(III) oxide and hydroxide are more acidic, showing that thallium conforms to the general rule of elements being more electropositive in their lower oxidation states. [13]

Thallium is malleable and sectile enough to be cut with a knife at room temperature. It has a metallic luster that, when exposed to air, quickly tarnishes to a bluish-gray tinge, resembling lead. It may be preserved by immersion in oil. A heavy layer of oxide builds up on thallium if left in air. In the presence of water, thallium hydroxide is formed. Sulfuric and nitric acids dissolve thallium rapidly to make the sulfate and nitrate salts, while hydrochloric acid forms an insoluble thallium(I) chloride layer. [14]

Isotopes

Thallium has 41 isotopes which have atomic masses that range from 176 to 216. 203Tl and 205Tl are the only stable isotopes and make up nearly all of natural thallium. The five short-lived isotopes 206Tl through 210Tl inclusive occur in nature, as they are part of the natural decay chains of heavier elements. 204Tl is the most stable radioisotope, with a half-life of 3.78 years. [15] It is made by the neutron activation of stable thallium in a nuclear reactor. [15] [16] The most useful radioisotope, 201Tl (half-life 73 hours), decays by electron capture, emitting X-rays (~70–80 keV), and photons of 135 and 167 keV in 10% total abundance; [15] therefore, it has good imaging characteristics without an excessive patient-radiation dose. It is the most popular isotope used for thallium nuclear cardiac stress tests. [17]

Compounds

Thallium(III)

Thallium(III) compounds resemble the corresponding aluminium(III) compounds. They are moderately strong oxidizing agents and are usually unstable, as illustrated by the positive reduction potential for the Tl3+/Tl couple. Some mixed-valence compounds are also known, such as Tl4O3 and TlCl2, which contain both thallium(I) and thallium(III). Thallium(III) oxide, Tl2O3, is a black solid which decomposes above 800 °C, forming the thallium(I) oxide and oxygen. [14]

The simplest possible thallium compound, thallane (TlH3), is too unstable to exist in bulk, both due to the instability of the +3 oxidation state as well as poor overlap of the valence 6s and 6p orbitals of thallium with the 1s orbital of hydrogen. [18] The trihalides are more stable, although they are chemically distinct from those of the lighter group 13 elements and are still the least stable in the whole group. For instance, thallium(III) fluoride, TlF3, has the β-BiF3 structure rather than that of the lighter group 13 trifluorides, and does not form the TlF−
4 complex anion in aqueous solution. The trichloride and tribromide disproportionate just above room temperature to give the monohalides, and thallium triiodide contains the linear triiodide anion (I−
3) and is actually a thallium(I) compound. [19] Thallium(III) sesquichalcogenides do not exist. [20]

Thallium(I)

The thallium(I) halides are stable. In keeping with the large size of the Tl+ cation, the chloride and bromide have the caesium chloride structure, while the fluoride and iodide have distorted sodium chloride structures. Like the analogous silver compounds, TlCl, TlBr, and TlI are photosensitive and display poor solubility in water. [21] The stability of thallium(I) compounds demonstrates its differences from the rest of the group: a stable oxide, hydroxide, and carbonate are known, as are many chalcogenides. [22]

The double salt Tl
4(OH)
2CO
3 has been shown to have hydroxyl-centred triangles of thallium, [Tl
3(OH)]2+
, as a recurring motif throughout its solid structure. [23]

The metalorganic compound thallium ethoxide (TlOEt, TlOC2H5) is a heavy liquid (ρ 3.49 g·cm−3, m.p. −3 °C), [24] often used as a basic and soluble thallium source in organic and organometallic chemistry. [25]

Organothallium compounds

Organothallium compounds tend to be thermally unstable, in concordance with the trend of decreasing thermal stability down group 13. The chemical reactivity of the Tl–C bond is also the lowest in the group, especially for ionic compounds of the type R2TlX. Thallium forms the stable [Tl(CH3)2]+ ion in aqueous solution; like the isoelectronic Hg(CH3)2 and [Pb(CH3)2]2+, it is linear. Trimethylthallium and triethylthallium are, like the corresponding gallium and indium compounds, flammable liquids with low melting points. Like indium, thallium cyclopentadienyl compounds contain thallium(I), in contrast to gallium(III). [26]

History

Thallium (Greek θαλλός, thallos, meaning "a green shoot or twig") [27] was discovered by William Crookes and Claude Auguste Lamy, working independently, both using flame spectroscopy (Crookes was first to publish his findings, on March 30, 1861). [28] The name comes from thallium's bright green spectral emission lines [29] derived from the Greek 'thallos', meaning a green twig. [30]

After the publication of the improved method of flame spectroscopy by Robert Bunsen and Gustav Kirchhoff [31] and the discovery of caesium and rubidium in the years 1859 to 1860, flame spectroscopy became an approved method to determine the composition of minerals and chemical products. Crookes and Lamy both started to use the new method. Crookes used it to make spectroscopic determinations for tellurium on selenium compounds deposited in the lead chamber of a sulfuric acid production plant near Tilkerode in the Harz mountains. He had obtained the samples for his research on selenium cyanide from August Hofmann years earlier. [32] [33] By 1862, Crookes was able to isolate small quantities of the new element and determine the properties of a few compounds. [34] Claude-Auguste Lamy used a spectrometer that was similar to Crookes' to determine the composition of a selenium-containing substance which was deposited during the production of sulfuric acid from pyrite. He also noticed the new green line in the spectra and concluded that a new element was present. Lamy had received this material from the sulfuric acid plant of his friend Frédéric Kuhlmann and this by-product was available in large quantities. Lamy started to isolate the new element from that source. [35] The fact that Lamy was able to work ample quantities of thallium enabled him to determine the properties of several compounds and in addition he prepared a small ingot of metallic thallium which he prepared by remelting thallium he had obtained by electrolysis of thallium salts.[ citation needed ]

As both scientists discovered thallium independently and a large part of the work, especially the isolation of the metallic thallium was done by Lamy, Crookes tried to secure his own priority on the work. Lamy was awarded a medal at the International Exhibition in London 1862: For the discovery of a new and abundant source of thallium and after heavy protest Crookes also received a medal: thallium, for the discovery of the new element. The controversy between both scientists continued through 1862 and 1863. Most of the discussion ended after Crookes was elected Fellow of the Royal Society in June 1863. [36] [37]

The dominant use of thallium was the use as poison for rodents. After several accidents the use as poison was banned in the United States by Presidential Executive Order 11643 in February 1972. In subsequent years several other countries also banned its use. [38]

Occurrence and production

Thallium concentration in the Earth's crust is estimated to be 0.7 mg/kg, [39] mostly in association with potassium-based minerals in clays, soils, and granites. The major source of thallium for practical purposes is the trace amount that is found in copper, lead, zinc, and other heavy-metal-sulfide ores. [40] [41]

Crystals of hutchinsonite ((Tl,Pb)2As5S9) Hutchinsonite-131710.jpg
Crystals of hutchinsonite ((Tl,Pb)2As5S9)

Thallium is found in the minerals crookesite TlCu7Se4, hutchinsonite TlPbAs5S9, and lorándite TlAsS2. [42] Thallium also occurs as a trace element in iron pyrite, and thallium is extracted as a by-product of roasting this mineral for the production of sulfuric acid. [9] [43]

Thallium can also be obtained from the smelting of lead and zinc ores. Manganese nodules found on the ocean floor contain some thallium. [44] In addition, several other thallium minerals, containing 16% to 60% thallium, occur in nature as complexes of sulfides or selenides that primarily contain antimony, arsenic, copper, lead, and silver. These minerals are rare, and have had no commercial importance as sources of thallium. [39] The Allchar deposit in southern North Macedonia was the only area where thallium was actively mined. This deposit still contains an estimated 500 tonnes of thallium, and it is a source for several rare thallium minerals, for example lorándite. [45]

The United States Geological Survey (USGS) estimates that the annual worldwide production of thallium is 10 metric tonnes as a by-product from the smelting of copper, zinc, and lead ores. [39] Thallium is either extracted from the dusts from the smelter flues or from residues such as slag that are collected at the end of the smelting process. [39] The raw materials used for thallium production contain large amounts of other materials and therefore a purification is the first step. The thallium is leached either by the use of a base or sulfuric acid from the material. The thallium is precipitated several times from the solution to remove impurities. At the end it is converted to thallium sulfate and the thallium is extracted by electrolysis on platinum or stainless steel plates. [43] The production of thallium decreased by about 33% in the period from 1995 to 2009 – from about 15 metric tonnes to about 10 tonnes. Since there are several small deposits or ores with relatively high thallium content, it would be possible to increase the production if a new application, such as a thallium-containing high-temperature superconductor, becomes practical for widespread use outside of the laboratory. [46]

Applications

Historic uses

The odorless and tasteless thallium sulfate was once widely used as rat poison and ant killer. Since 1972 this use has been prohibited in the United States due to safety concerns. [38] [9] Many other countries followed this example. Thallium salts were used in the treatment of ringworm, other skin infections and to reduce the night sweating of tuberculosis patients. This use has been limited due to their narrow therapeutic index, and the development of improved medicines for these conditions. [47] [48] [49]

Optics

Thallium(I) bromide and thallium(I) iodide crystals have been used as infrared optical materials, because they are harder than other common infrared optics, and because they have transmission at significantly longer wavelengths. The trade name KRS-5 refers to this material. [50] Thallium(I) oxide has been used to manufacture glasses that have a high index of refraction. Combined with sulfur or selenium and arsenic, thallium has been used in the production of high-density glasses that have low melting points in the range of 125 and 150 Celsius°. These glasses have room-temperature properties that are similar to ordinary glasses and are durable, insoluble in water and have unique refractive indices. [51]

Electronics

A corroded thallium rod Thallium rod corroded.jpg
A corroded thallium rod

Thallium(I) sulfide's electrical conductivity changes with exposure to infrared light, making this compound useful in photoresistors. [47] Thallium selenide has been used in bolometers for infrared detection. [52] Doping selenium semiconductors with thallium improves their performance, thus it is used in trace amounts in selenium rectifiers. [47] Another application of thallium doping is the sodium iodide and cesium iodide crystals in gamma radiation detection devices. In these, the sodium iodide crystals are doped with a small amount of thallium to improve their efficiency as scintillation generators. [53] Some of the electrodes in dissolved oxygen analyzers contain thallium. [9]

High-temperature superconductivity

Research activity with thallium is ongoing to develop high-temperature superconducting materials for such applications as magnetic resonance imaging, storage of magnetic energy, magnetic propulsion, and electric power generation and transmission. The research in applications started after the discovery of the first thallium barium calcium copper oxide superconductor in 1988. [54] Thallium cuprate superconductors have been discovered that have transition temperatures above 120 K. Some mercury-doped thallium-cuprate superconductors have transition temperatures above 130 K at ambient pressure, nearly as high as the world-record-holding mercury cuprates. [55]

Nuclear medicine

Before the widespread application of technetium-99m in nuclear medicine, the radioactive isotope thallium-201, with a half-life of 73 hours, was the main substance for nuclear cardiography. The nuclide is still used for stress tests for risk stratification in patients with coronary artery disease (CAD). [56] This isotope of thallium can be generated using a transportable generator, which is similar to the technetium-99m generator. [57] The generator contains lead-201 (half-life 9.33 hours), which decays by electron capture to thallium-201. The lead-201 can be produced in a cyclotron by the bombardment of thallium with protons or deuterons by the (p,3n) and (d,4n) reactions. [58] [59]

Thallium stress test

A thallium stress test is a form of scintigraphy in which the amount of thallium in tissues correlates with tissue blood supply. Viable cardiac cells have normal Na+/K+ ion-exchange pumps. The Tl+ cation binds the K+ pumps and is transported into the cells. Exercise or dipyridamole induces widening (vasodilation) of arteries in the body. This produces coronary steal by areas where arteries are maximally dilated. Areas of infarct or ischemic tissue will remain "cold". Pre- and post-stress thallium may indicate areas that will benefit from myocardial revascularization. Redistribution indicates the existence of coronary steal and the presence of ischemic coronary artery disease. [60]

Other uses

A mercury–thallium alloy, which forms a eutectic at 8.5% thallium, is reported to freeze at −60 °C, some 20 °C below the freezing point of mercury. This alloy is used in thermometers and low-temperature switches. [47] In organic synthesis, thallium(III) salts, as thallium trinitrate or triacetate, are useful reagents for performing different transformations in aromatics, ketones and olefins, among others. [61] Thallium is a constituent of the alloy in the anode plates of magnesium seawater batteries. [9] Soluble thallium salts are added to gold plating baths to increase the speed of plating and to reduce grain size within the gold layer. [62]

A saturated solution of equal parts of thallium(I) formate (Tl(HCO2)) and thallium(I) malonate (Tl(C3H3O4)) in water is known as Clerici solution. It is a mobile, odorless liquid which changes from yellowish to colorless upon reducing the concentration of the thallium salts. With a density of 4.25 g/cm3 at 20 °C, Clerici solution is one of the heaviest aqueous solutions known. It was used in the 20th century for measuring the density of minerals by the flotation method, but its use has discontinued due to the high toxicity and corrosiveness of the solution. [63] [64]

Thallium iodide is frequently used as an additive in metal-halide lamps, often together with one or two halides of other metals. It allows optimization of the lamp temperature and color rendering, [65] [66] and shifts the spectral output to the green region, which is useful for underwater lighting. [67]

Toxicity

Thallium
Hazards
GHS labelling:
GHS-pictogram-skull.svg GHS-pictogram-silhouette.svg GHS-pictogram-pollu.svg
Danger
H300, H330, H373, H413
P260, P264, P284, P301, P310 [68]
NFPA 704 (fire diamond)
NFPA 704.svgHealth 4: Very short exposure could cause death or major residual injury. E.g. VX gasFlammability 0: Will not burn. E.g. waterInstability 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g. white phosphorusSpecial hazards (white): no code
4
0
2

Thallium and its compounds are extremely toxic, with numerous recorded cases of fatal thallium poisoning. [69] [70] The Occupational Safety and Health Administration (OSHA) has set the legal limit (permissible exposure limit) for thallium exposure in the workplace as 0.1 mg/m2 skin exposure over an eight-hour workday. The National Institute for Occupational Safety and Health (NIOSH) also set a recommended exposure limit (REL) of 0.1 mg/m2 skin exposure over an eight-hour workday. At levels of 15 mg/m2, thallium is immediately dangerous to life and health. [71]

Contact with skin is dangerous, and adequate ventilation is necessary when melting this metal. Thallium(I) compounds have a high aqueous solubility and are readily absorbed through the skin, and care should be taken to avoid this route of exposure, as cutaneous absorption can exceed the absorbed dose received by inhalation at the permissible exposure limit (PEL). [72] Exposure by inhalation cannot safely exceed 0.1 mg/m2 in an eight-hour time-weighted average (40-hour work week). [73] The Centers for Disease Control and Prevention (CDC) states, "Thallium is not classifiable as a carcinogen, and it is not suspected to be a carcinogen. It is unknown whether chronic or repeated exposure to thallium increases the risk of reproductive toxicity or developmental toxicity. Chronic high level exposure to thallium through inhalation has been reported to cause nervous system effects, such as numbness of fingers and toes." [74] For a long time thallium compounds were readily available as rat poison. This fact and that it is water-soluble and nearly tasteless led to frequent intoxication caused by accident or criminal intent. [37]

One of the main methods of removing thallium (both radioactive and stable) from humans is to use Prussian blue, a material which absorbs thallium. [75] Up to 20 grams per day of Prussian blue is fed by mouth to the patient, and it passes through their digestive system and comes out in their stool. Hemodialysis and hemoperfusion are also used to remove thallium from the blood serum. At later stages of the treatment, additional potassium is used to mobilize thallium from the tissues. [76] [77]

According to the United States Environmental Protection Agency (EPA), artificially-made sources of thallium pollution include gaseous emission of cement factories, coal-burning power plants, and metal sewers. The main source of elevated thallium concentrations in water is the leaching of thallium from ore processing operations. [41] [78]

See also

Citations

  1. ↑ "Standard Atomic Weights: Thallium". CIAAW. 2009.
  2. ↑ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN   1365-3075.
  3. 1 2 Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. ISBN   978-1-62708-155-9.
  4. ↑ Dong, Z.-C.; Corbett, J. D. (1996). "Na23K9Tl15.3: An Unusual Zintl Compound Containing Apparent Tl57−, Tl48−, Tl37−, and Tl5− Anions". Inorganic Chemistry. 35 (11): 3107–12. doi:10.1021/ic960014z. PMID   11666505.
  5. ↑ Lide, D. R., ed. (2005). "Magnetic susceptibility of the elements and inorganic compounds". CRC Handbook of Chemistry and Physics (PDF) (86th ed.). Boca Raton (FL): CRC Press. ISBN   0-8493-0486-5.
  6. ↑ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN   0-8493-0464-4.
  7. ↑ Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
  8. ↑ The Mining and Smelting Magazine Archived 2021-02-24 at the Wayback Machine . Ed. Henry Curwen Salmon. Vol. iv, July–Dec 1963, p. 87.
  9. 1 2 3 4 5 "Chemical fact sheet – Thallium". Spectrum Laboratories. April 2001. Archived from the original on 2008-02-21. Retrieved 2008-02-02.
  10. ↑ Hasan, Heather (2009). The Boron Elements: Boron, Aluminum, Gallium, Indium, Thallium. Rosen Publishing Group. p. 14. ISBN   978-1-4358-5333-1.
  11. 1 2 3 Greenwood and Earnshaw, pp. 222–224
  12. ↑ Haynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nd ed.). Boca Raton, FL: CRC Press. p. 8.20. ISBN   1-4398-5511-0.
  13. 1 2 Greenwood and Earnshaw, pp. 224–7
  14. 1 2 Holleman, Arnold F.; Wiberg, Egon; Wiberg, Nils (1985). "Thallium". Lehrbuch der Anorganischen Chemie (in German) (91–100 ed.). Walter de Gruyter. pp. 892–893. ISBN   978-3-11-007511-3.
  15. 1 2 3 Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
  16. ↑ "Manual for reactor produced radioisotopes" (PDF). International Atomic Energy Agency. 2003. Archived (PDF) from the original on 2011-05-21. Retrieved 2010-05-13.
  17. ↑ Maddahi, Jamshid; Berman, Daniel (2001). "Detection, Evaluation, and Risk Stratification of Coronary Artery Disease by Thallium-201 Myocardial Perfusion Scintigraphy 155". Cardiac SPECT imaging (2nd ed.). Lippincott Williams & Wilkins. pp. 155–178. ISBN   978-0-7817-2007-6. Archived from the original on 2017-02-22. Retrieved 2016-09-26.
  18. ↑ Andrew, L.; Wang, X. (2004). "Infrared Spectra of Thallium Hydrides in Solid Neon, Hydrogen, and Argon". J. Phys. Chem. A. 108 (16): 3396–3402. Bibcode:2004JPCA..108.3396W. doi:10.1021/jp0498973.
  19. ↑ Greenwood and Earnshaw, p. 239
  20. ↑ Greenwood and Earnshaw, p. 254
  21. ↑ Greenwood and Earnshaw, p. 241
  22. ↑ Greenwood and Earnshaw, pp. 246–7
  23. ↑ Siidra, Oleg I.; Britvin, Sergey N.; Krivovichev, Sergey V. (2009). "Hydroxocentered [(OH)Tl
    3    ]2+
     triangle as a building unit in thallium compounds: synthesis and crystal structure of Tl
    4    (OH)
    2    CO
    3    ". Z. Kristallogr. 224 (12): 563–567. Bibcode:2009ZK....224..563S. doi:10.1524/zkri.2009.1213. S2CID   97334707.
  24. ↑ Handbook of inorganic compounds. Perry, Dale L., Phillips, Sidney L. Boca Raton: CRC Press. 1995. ISBN   0-8493-8671-3. OCLC   32347397.{{cite book}}: CS1 maint: others (link)
  25. ↑ Frank, Scott A.; Chen, Hou; Kunz, Roxanne K.; Schnaderbeck, Matthew J.; Roush, William R. (2000-08-01). "Use of Thallium(I) Ethoxide in Suzuki Cross Coupling Reactions". Organic Letters. 2 (17): 2691–2694. doi:10.1021/ol0062446. ISSN   1523-7060. PMID   10990429.
  26. ↑ Greenwood and Earnshaw, pp. 262–4
  27. ↑ Liddell, Henry George and Scott, Robert (eds.) "θαλλος Archived 2016-04-15 at the Wayback Machine ", in A Greek–English Lexicon , Oxford University Press.
  28. ↑
    • Crookes, William (March 30, 1861) "On the existence of a new element, probably of the sulphur group," Chemical News, vol. 3, pp. 193–194; reprinted in: Crookes, William (April 1861). "XLVI. On the existence of a new element, probably of the sulphur group". Philosophical Magazine. 21 (140): 301–305. doi:10.1080/14786446108643058. Archived from the original on 2014-07-01. Retrieved 2016-09-26.;
    • Crookes, William (May 18, 1861) "Further remarks on the supposed new metalloid," Chemical News, vol. 3, p. 303.
    • Crookes, William (June 19, 1862) "Preliminary researches on thallium," Proceedings of the Royal Society of London, vol. 12, pages 150–159.
    • Lamy, A. (May 16, 1862) "De l'existencè d'un nouveau métal, le thallium," Comptes Rendus, vol. 54, pages 1255–1262 Archived 2016-05-15 at the Portuguese Web Archive.
  29. ↑ Weeks, Mary Elvira (1932). "The discovery of the elements. XIII. Supplementary note on the discovery of thallium". Journal of Chemical Education. 9 (12): 2078. Bibcode:1932JChEd...9.2078W. doi:10.1021/ed009p2078.
  30. ↑ "Thallium - Element information, properties and uses | Periodic Table". Royal Society of Chemistry. Retrieved 2 February 2024.
  31. ↑ G. Kirchhoff; R. Bunsen (1861). "Chemische Analyse durch Spectralbeobachtungen" (PDF). Annalen der Physik und Chemie . 189 (7): 337–381. Bibcode:1861AnP...189..337K. doi:10.1002/andp.18611890702. Archived (PDF) from the original on 2020-11-14. Retrieved 2018-04-20.
  32. ↑ Crookes, William (1862–1863). "Preliminary Researches on Thallium". Proceedings of the Royal Society of London. 12: 150–159. Bibcode:1862RSPS...12..150C. doi: 10.1098/rspl.1862.0030 . JSTOR   112218.
  33. ↑ Crookes, William (1863). "On Thallium". Philosophical Transactions of the Royal Society of London. 153: 173–192. doi: 10.1098/rstl.1863.0009 . JSTOR   108794. Archived from the original on 2020-03-13. Retrieved 2019-09-12.
  34. ↑ DeKosky, Robert K. (1973). "Spectroscopy and the Elements in the Late Nineteenth Century: The Work of Sir William Crookes". The British Journal for the History of Science. 6 (4): 400–423. doi:10.1017/S0007087400012553. JSTOR   4025503. S2CID   146534210.
  35. ↑ Lamy, Claude-Auguste (1862). "De l'existencè d'un nouveau métal, le thallium". Comptes Rendus. 54: 1255–1262. Archived from the original on 2016-05-15. Retrieved 2008-11-11.
  36. ↑ James, Frank A. J. L. (1984). "Of 'Medals and Muddles' the Context of the Discovery of Thallium: William Crookes's Early". Notes and Records of the Royal Society of London. 39 (1): 65–90. doi: 10.1098/rsnr.1984.0005 . JSTOR   531576.
  37. 1 2 Emsley, John (2006). "Thallium". The Elements of Murder: A History of Poison. Oxford University Press. pp. 326–327. ISBN   978-0-19-280600-0. Archived from the original on 2020-03-07. Retrieved 2016-09-26.
  38. 1 2 Staff of the Nonferrous Metals Division (1972). "Thallium". Minerals yearbook metals, minerals, and fuels. Vol. 1. United States Geological Survey. p. 1358. Archived from the original on 2014-03-22. Retrieved 2010-06-01.
  39. 1 2 3 4 Guberman, David E. "Mineral Commodity Summaries 2010: Thallium" (PDF). United States Geological Survey. Archived (PDF) from the original on 2010-07-15. Retrieved 2010-05-13.
  40. ↑ Zitko, V.; Carson, W. V.; Carson, W. G. (1975). "Thallium: Occurrence in the environment and toxicity to fish". Bulletin of Environmental Contamination and Toxicology. 13 (1): 23–30. Bibcode:1975BuECT..13...23Z. doi:10.1007/BF01684859. PMID   1131433. S2CID   40955658.
  41. 1 2 Peter, A.; Viraraghavan, T. (2005). "Thallium: a review of public health and environmental concerns". Environment International . 31 (4): 493–501. doi:10.1016/j.envint.2004.09.003. PMID   15788190.
  42. ↑ Shaw, D. (1952). "The geochemistry of thallium". Geochimica et Cosmochimica Acta. 2 (2): 118–154. Bibcode:1952GeCoA...2..118S. doi:10.1016/0016-7037(52)90003-3.
  43. 1 2 Downs, Anthony John (1993). Chemistry of aluminium, gallium, indium, and thallium. Springer. pp. 90 and 106. ISBN   978-0-7514-0103-5. Archived from the original on 2017-02-22. Retrieved 2016-09-26.
  44. ↑ Rehkamper, M.; Nielsen, Sune G. (2004). "The mass balance of dissolved thallium in the oceans". Marine Chemistry. 85 (3–4): 125–139. Bibcode:2004MarCh..85..125R. doi:10.1016/j.marchem.2003.09.006.
  45. ↑ Jankovic, S. (1988). "The Allchar Tl–As–Sb deposit, Yugoslavia and its specific metallogenic features". Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 271 (2): 286. Bibcode:1988NIMPA.271..286J. doi:10.1016/0168-9002(88)90170-2.
  46. ↑ Smith, Gerald R. "Mineral commodity summaries 1996: Thallium" (PDF). United States Geological Survey. Archived (PDF) from the original on 2010-05-29. Retrieved 2010-05-13.
  47. 1 2 3 4 Hammond, C. R. (2004-06-29). The Elements, in Handbook of Chemistry and Physics (81st ed.). CRC press. ISBN   978-0-8493-0485-9.
  48. ↑ Percival, G. H. (1930). "The Treatment of Ringworm of The Scalp with Thallium Acetate". British Journal of Dermatology. 42 (2): 59–69. doi:10.1111/j.1365-2133.1930.tb09395.x. PMC   2456722 . PMID   20774304.
  49. ↑ Galvanarzate, S.; Santamarı́a, A. (1998). "Thallium toxicity". Toxicology Letters . 99 (1): 1–13. doi:10.1016/S0378-4274(98)00126-X. PMID   9801025.
  50. ↑ Rodney, William S.; Malitson, Irving H. (1956). "Refraction and Dispersion of Thallium Bromide Iodide". Journal of the Optical Society of America . 46 (11): 338–346. Bibcode:1956JOSA...46..956R. doi:10.1364/JOSA.46.000956.
  51. ↑ Kokorina, Valentina F. (1996). Glasses for infrared optics. CRC Press. ISBN   978-0-8493-3785-7. Archived from the original on 2020-03-11. Retrieved 2016-09-26.
  52. ↑ Nayer, P. S; Hamilton, O. (1977). "Thallium selenide infrared detector". Appl. Opt. 16 (11): 2942–4. Bibcode:1977ApOpt..16.2942N. doi:10.1364/AO.16.002942. PMID   20174271.
  53. ↑ Hofstadter, Robert (1949). "The Detection of Gamma-Rays with Thallium-Activated Sodium Iodide Crystals". Physical Review. 75 (5): 796–810. Bibcode:1949PhRv...75..796H. doi:10.1103/PhysRev.75.796.
  54. ↑ Sheng, Z. Z.; Hermann A. M. (1988). "Bulk superconductivity at 120 K in the Tl–Ca/Ba–Cu–O system". Nature. 332 (6160): 138–139. Bibcode:1988Natur.332..138S. doi:10.1038/332138a0. S2CID   30690410.
  55. ↑ Jia, Y. X.; Lee, C. S.; Zettl, A. (1994). "Stabilization of the Tl2Ba2Ca2Cu3O10 superconductor by Hg doping". Physica C. 234 (1–2): 24–28. Bibcode:1994PhyC..234...24J. doi:10.1016/0921-4534(94)90049-3. Archived from the original on 2020-03-16. Retrieved 2019-07-01.
  56. ↑ Jain, Diwakar; Zaret, Barry L. (2005). "Nuclear imaging in cardiovascular medicine". In Clive Rosendorff (ed.). Essential cardiology: principles and practice (2nd ed.). Humana Press. pp. 221–222. ISBN   978-1-58829-370-1. Archived from the original on 2017-02-19. Retrieved 2016-09-26.
  57. ↑ Lagunas-Solar, M. C.; Little, F. E.; Goodart, C. D. (1982). "An integrally shielded transportable generator system for thallium-201 production". International Journal of Applied Radiation and Isotopes. 33 (12): 1439–1443. doi:10.1016/0020-708X(82)90183-1. PMID   7169272. Archived from the original on 2007-10-12. Retrieved 2006-11-23.
  58. ↑ Thallium-201 production Archived 2006-09-13 at the Wayback Machine from Harvard Medical School's Joint Program in Nuclear Medicine.
  59. ↑ Lebowitz, E.; Greene, M. W.; Fairchild, R.; Bradley-Moore, P. R.; Atkins, H. L.; Ansari, A. N.; Richards, P.; Belgrave, E. (1975). "Thallium-201 for medical use". The Journal of Nuclear Medicine. 16 (2): 151–5. PMID   1110421. Archived from the original on 2008-10-11. Retrieved 2010-05-13.
  60. ↑ Taylor, George J. (2004). Primary care cardiology. Wiley-Blackwell. p. 100. ISBN   978-1-4051-0386-2. Archived from the original on 2020-03-12. Retrieved 2016-09-26.
  61. ↑ Taylor, Edward Curtis; McKillop, Alexander (1970). "Thallium in organic synthesis". Accounts of Chemical Research. 3 (10): 956–960. doi:10.1021/ar50034a003.
  62. ↑ Pecht, Michael (1994-03-01). Integrated circuit, hybrid, and multichip module package design guidelines: a focus on reliability. John Wiley & Sons. pp. 113–115. ISBN   978-0-471-59446-8. Archived from the original on 2014-07-01. Retrieved 2016-09-26.
  63. ↑ Jahns, R. H. (1939). "Clerici solution for the specific gravity determination of small mineral grains" (PDF). American Mineralogist. 24: 116. Archived (PDF) from the original on 2012-07-24. Retrieved 2009-11-06.
  64. ↑ Peter G. Read (1999). Gemmology. Butterworth-Heinemann. pp. 63–64. ISBN   978-0-7506-4411-2. Archived from the original on 2020-03-17. Retrieved 2016-09-26.
  65. ↑ Reiling, Gilbert H. (1964). "Characteristics of Mercury Vapor-Metallic Iodide Arc Lamps". Journal of the Optical Society of America. 54 (4): 532. Bibcode:1964JOSA...54..532R. doi:10.1364/JOSA.54.000532.
  66. ↑ Gallo, C. F. (1967). "The Effect of Thallium Iodide on the Arc Temperature of Hg Discharges". Applied Optics. 6 (9): 1563–5. Bibcode:1967ApOpt...6.1563G. doi:10.1364/AO.6.001563. PMID   20062260.
  67. ↑ Wilford, John Noble (1987-08-11). "UNDERSEA QUEST FOR GIANT SQUIDS AND RARE SHARKS". The New York Times. Archived from the original on 2016-12-20. Retrieved 2017-02-13.
  68. ↑ "Thallium 277932". Sigma-Aldrich. Archived from the original on 2018-10-02. Retrieved 2018-10-02.
  69. ↑ "A 15-year-old case yields a timely clue in deadly thallium poisoning". nj. 2011-02-13. Retrieved 2023-02-12.
  70. ↑ Jennifer Ouellette (25 December 2018). "Study brings us one step closer to solving 1994 thallium poisoning case". Ars Technica. Archived from the original on 26 December 2018. Retrieved 26 December 2018.
  71. ↑ "CDC – NIOSH Pocket Guide to Chemical Hazards – Thallium (soluble compounds, as Tl)". www.cdc.gov. Archived from the original on 2015-09-24. Retrieved 2015-11-24.
  72. ↑ "Surface Contamination - Overview | Occupational Safety and Health Administration". www.osha.gov. Retrieved 2023-02-12.
  73. ↑ Chemical Sampling Information | Thallium, soluble compounds (as Tl) Archived 2014-03-22 at the Wayback Machine . Osha.gov. Retrieved on 2013-09-05.
  74. ↑ "CDC – The Emergency Response Safety and Health Database: Systemic Agent: THALLIUM – NIOSH". www.cdc.gov. Archived from the original on 2019-11-15. Retrieved 2019-12-11.
  75. ↑ Yang, Yongsheng; Faustino, Patrick J.; Progar, Joseph J.; et al. (2008). "Quantitative determination of thallium binding to ferric hexacyanoferrate: Prussian blue". International Journal of Pharmaceutics. 353 (1–2): 187–194. doi:10.1016/j.ijpharm.2007.11.031. PMID   18226478. Archived from the original on 2020-03-15. Retrieved 2019-07-01.
  76. ↑ Prussian blue fact sheet Archived 2013-10-20 at the Wayback Machine . US Centers for Disease Control and Prevention.
  77. ↑ Malbrain, Manu L. N. G.; Lambrecht, Guy L. Y.; Zandijk, Erik; Demedts, Paul A.; Neels, Hugo M.; Lambert, Willy; De Leenheer, André P.; Lins, Robert L.; Daelemans, Ronny (1997). "Treatment of Severe Thallium Intoxication". Clinical Toxicology. 35 (1): 97–100. doi:10.3109/15563659709001173. PMID   9022660.
  78. ↑ "Factsheet on: Thallium" (PDF). US Environmental Protection Agency. Archived (PDF) from the original on 2012-01-11. Retrieved 2009-09-15.

General bibliography

Related Research Articles

<span class="mw-page-title-main">Alkali metal</span> Group of highly reactive chemical elements

The alkali metals consist of the chemical elements lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr). Together with hydrogen they constitute group 1, which lies in the s-block of the periodic table. All alkali metals have their outermost electron in an s-orbital: this shared electron configuration results in their having very similar characteristic properties. Indeed, the alkali metals provide the best example of group trends in properties in the periodic table, with elements exhibiting well-characterised homologous behaviour. This family of elements is also known as the lithium family after its leading element.

<span class="mw-page-title-main">Bromine</span> Chemical element, symbol Br and atomic number 35

Bromine is a chemical element; it has symbol Br and atomic number 35. It is a volatile red-brown liquid at room temperature that evaporates readily to form a similarly coloured vapour. Its properties are intermediate between those of chlorine and iodine. Isolated independently by two chemists, Carl Jacob Löwig and Antoine Jérôme Balard, its name was derived from the Ancient Greek βρῶμος (bromos) meaning "stench", referring to its sharp and pungent smell.

<span class="mw-page-title-main">Calcium</span> Chemical element, symbol Ca and atomic number 20

Calcium is a chemical element; it has symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to its heavier homologues strontium and barium. It is the fifth most abundant element in Earth's crust, and the third most abundant metal, after iron and aluminium. The most common calcium compound on Earth is calcium carbonate, found in limestone and the fossilised remnants of early sea life; gypsum, anhydrite, fluorite, and apatite are also sources of calcium. The name derives from Latin calx "lime", which was obtained from heating limestone.

<span class="mw-page-title-main">Chalcogen</span> Group of chemical elements

The chalcogens are the chemical elements in group 16 of the periodic table. This group is also known as the oxygen family. Group 16 consists of the elements oxygen (O), sulfur (S), selenium (Se), tellurium (Te), and the radioactive elements polonium (Po) and livermorium (Lv). Often, oxygen is treated separately from the other chalcogens, sometimes even excluded from the scope of the term "chalcogen" altogether, due to its very different chemical behavior from sulfur, selenium, tellurium, and polonium. The word "chalcogen" is derived from a combination of the Greek word khalkόs (χαλκός) principally meaning copper, and the Latinized Greek word genēs, meaning born or produced.

<span class="mw-page-title-main">Indium</span> Chemical element, symbol In and atomic number 49

Indium is a chemical element; it has symbol In and atomic number 49. It is a silvery-white post-transition metal and one of the softest elements. Chemically, indium is similar to gallium and thallium, and its properties are largely intermediate between the two. It was discovered in 1863 by Ferdinand Reich and Hieronymous Theodor Richter by spectroscopic methods and named for the indigo blue line in its spectrum.

<span class="mw-page-title-main">Iodine</span> Chemical element, symbol I and atomic number 53

Iodine is a chemical element; it has symbol I and atomic number 53. The heaviest of the stable halogens, it exists at standard conditions as a semi-lustrous, non-metallic solid that melts to form a deep violet liquid at 114 °C (237 °F), and boils to a violet gas at 184 °C (363 °F). The element was discovered by the French chemist Bernard Courtois in 1811 and was named two years later by Joseph Louis Gay-Lussac, after the Ancient Greek Ιώδης, meaning 'violet'.

<span class="mw-page-title-main">Lanthanum</span> Chemical element, symbol La and atomic number 57

Lanthanum is a chemical element; it has symbol La and atomic number 57. It is a soft, ductile, silvery-white metal that tarnishes slowly when exposed to air. It is the eponym of the lanthanide series, a group of 15 similar elements between lanthanum and lutetium in the periodic table, of which lanthanum is the first and the prototype. Lanthanum is traditionally counted among the rare earth elements. Like most other rare earth elements, the usual oxidation state is +3, although some compounds are known with an oxidation state of +2. Lanthanum has no biological role in humans but is essential to some bacteria. It is not particularly toxic to humans but does show some antimicrobial activity.

<span class="mw-page-title-main">Thorium</span> Chemical element, symbol Th and atomic number 90

Thorium is a chemical element. It has the symbol Th and atomic number 90. Thorium is a weakly radioactive light silver metal which tarnishes olive gray when it is exposed to air, forming thorium dioxide; it is moderately soft and malleable and has a high melting point. Thorium is an electropositive actinide whose chemistry is dominated by the +4 oxidation state; it is quite reactive and can ignite in air when finely divided.

<span class="mw-page-title-main">Boron group</span> Chemical elements in group 13 of the periodic table

The boron group are the chemical elements in group 13 of the periodic table, consisting of boron (B), aluminium (Al), gallium (Ga), indium (In), thallium (Tl) and nihonium (Nh). This group lies in the p-block of the periodic table. The elements in the boron group are characterized by having three valence electrons. These elements have also been referred to as the triels.

A period 5 element is one of the chemical elements in the fifth row of the periodic table of the chemical elements. The periodic table is laid out in rows to illustrate recurring (periodic) trends in the chemical behaviour of the elements as their atomic number increases: a new row is begun when chemical behaviour begins to repeat, meaning that elements with similar behaviour fall into the same vertical columns. The fifth period contains 18 elements, beginning with rubidium and ending with xenon. As a rule, period 5 elements fill their 5s shells first, then their 4d, and 5p shells, in that order; however, there are exceptions, such as rhodium.

A period 6 element is one of the chemical elements in the sixth row (or period) of the periodic table of the chemical elements, including the lanthanides. The periodic table is laid out in rows to illustrate recurring (periodic) trends in the chemical behaviour of the elements as their atomic number increases: a new row is begun when chemical behaviour begins to repeat, meaning that elements with similar behaviour fall into the same vertical columns. The sixth period contains 32 elements, tied for the most with period 7, beginning with caesium and ending with radon. Lead is currently the last stable element; all subsequent elements are radioactive. For bismuth, however, its only primordial isotope, 209Bi, has a half-life of more than 1019 years, over a billion times longer than the current age of the universe. As a rule, period 6 elements fill their 6s shells first, then their 4f, 5d, and 6p shells, in that order; however, there are exceptions, such as gold.

<span class="mw-page-title-main">Group 4 element</span> Group of chemical elements

Group 4 is the second group of transition metals in the periodic table. It contains the four elements titanium (Ti), zirconium (Zr), hafnium (Hf), and rutherfordium (Rf). The group is also called the titanium group or titanium family after its lightest member.

<span class="mw-page-title-main">Group 5 element</span> Group of elements in the periodic table

Group 5 is a group of elements in the periodic table. Group 5 contains vanadium (V), niobium (Nb), tantalum (Ta) and dubnium (Db). This group lies in the d-block of the periodic table. This group is sometimes called the vanadium group or vanadium family after its lightest member; however, the group itself has not acquired a trivial name because it belongs to the broader grouping of the transition metals.

An iodide ion is the ion I−. Compounds with iodine in formal oxidation state −1 are called iodides. In everyday life, iodide is most commonly encountered as a component of iodized salt, which many governments mandate. Worldwide, iodine deficiency affects two billion people and is the leading preventable cause of intellectual disability.

The inert-pair effect is the tendency of the two electrons in the outermost atomic s-orbital to remain unshared in compounds of post-transition metals. The term inert-pair effect is often used in relation to the increasing stability of oxidation states that are two less than the group valency for the heavier elements of groups 13, 14, 15 and 16. The term "inert pair" was first proposed by Nevil Sidgwick in 1927. The name suggests that the outermost s electron pairs are more tightly bound to the nucleus in these atoms, and therefore more difficult to ionize or share.

<span class="mw-page-title-main">Sodium iodide</span> Chemical compound

Sodium iodide (chemical formula NaI) is an ionic compound formed from the chemical reaction of sodium metal and iodine. Under standard conditions, it is a white, water-soluble solid comprising a 1:1 mix of sodium cations (Na+) and iodide anions (I−) in a crystal lattice. It is used mainly as a nutritional supplement and in organic chemistry. It is produced industrially as the salt formed when acidic iodides react with sodium hydroxide. It is a chaotropic salt.

<span class="mw-page-title-main">Thallium(I) chloride</span> Chemical compound

Thallium(I) chloride, also known as thallous chloride, is a chemical compound with the formula TlCl. This colourless salt is an intermediate in the isolation of thallium from its ores. Typically, an acidic solution of thallium(I) sulfate is treated with hydrochloric acid to precipitate insoluble thallium(I) chloride. This solid crystallizes in the caesium chloride motif.

<span class="mw-page-title-main">Thallium(I) iodide</span> Chemical compound

Thallium(I) iodide is a chemical compound with the formula TlI. It is unusual in being one of the few water-insoluble metal iodides, along with AgI, CuI, SnI2, SnI4, PbI2 and HgI2.

The thallium halides include monohalides, where thallium has oxidation state +1, trihalides in which thallium generally has oxidation state +3, and some intermediate halides containing thallium with mixed +1 and +3 oxidation states. These salts find use in specialized optical settings, such as focusing elements in research spectrophotometers. Compared to the more common zinc selenide-based optics, materials such as thallium bromoiodide enable transmission at longer wavelengths. In the infrared, this allows for measurements as low as 350 cm−1 (28 μm), whereas zinc selenide is opaque by 21.5 μm, and ZnSe optics are generally only usable to 650 cm−1 (15 μm).

<span class="mw-page-title-main">Cerium</span> Chemical element, symbol Ce and atomic number 58

Cerium is a chemical element; it has symbol Ce and atomic number 58. Cerium is a soft, ductile, and silvery-white metal that tarnishes when exposed to air. Cerium is the second element in the lanthanide series, and while it often shows the oxidation state of +3 characteristic of the series, it also has a stable +4 state that does not oxidize water. It is also considered one of the rare-earth elements. Cerium has no known biological role in humans but is not particularly toxic, except with intense or continued exposure.

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.