Thallium/iodide

The attenuated total reflectance (ATR) technique is used commonly in the near-infrared for obtaining absorption spectra of thin Aims and opaque materials. The sample, of refractive index i, is placed in direct contact with a material which is transparent in the region of interest, such as thallium bromide/thallium iodide (known as KRS-5), silver chloride or germanium, of relatively high refractive index so that Then, as Figure 3.f8... 

Uses. Tballium compounds have limited use in industrial appHcations. The use of thaHous sulfate in rodenticides and insecticides has been replaced by other compounds less harmful to animals (see Insect control technology Pesticides). Tb allium sulfide has been used in photoelectric cells (see Photovoltaic cells). A thallium bromide—thallium iodide mixture is used to transmit infrared radiation for signal systems. ThaHous oxide is used in the manufacture of glass (qv) that has a high coefficient of refraction. Tb allium formate—malonate aqueous solutions (Cletici s solution) have been used in mineral separations. Many thallium compounds have been used as reagents in organic synthesis in researchlaboratoti.es. 

The reaction is generally carried out by refluxing a stirred mixture of 0.014 mole of the nitro compound and 0.042 mole (8.5 gm) of thallium in 75 ml of ethanol for the periods shown in Table I. The cooled solution is decanted to remove unreacted thallium, 8 gm of potassium iodide is added, and the mixture is stirred for 1 hr at room temperature. The precipitated thallium iodide is filtered, and the filtrate concentrated under reduced pressure. The residue is dissolved in chloroform and then filtered through an alumina column (4 x 1 in.) to remove traces of inorganic salts. Chloroform is used as the eluent, and the resulting solution is concentrated under reduced pressure to afford the solid azoxy compounds. 

All metallic iodides except silver iodide, mercurous iodide, mercuric iodide, lead iodide, cuprous nidide. thallium iodide, and palladium iodide, are soluble. The iodides of antimony, bismuth, tin require a little free acid to keep them in solulion. 

The most versatile method for measuring radiation in the laboratory is the scintillation counter, in which a substance called a phosphor, often a sodium iodide crystal containing a small amount of thallium iodide, emits a flash of light when struck by radiation. The number of flashes is counted electronically and converted into an electrical signal. 

Thallium iodide-thallium bromide (KRS-5) 16,000-250 2.37 Relatively soft, deforms easily warm water, ionizable acids and bases, chlorinated solvents, and amines should not be used with this ATR element... 

Organic compoimds that contain nitrogen in a hmctional groi shoitid not be used with plates whidi are made of thallium bromide and thallium iodide (KRS-5 plates) as they pereact with the plates. Despite these disadvantages, the tedmique is still a most usefiti one for solid ugs. The advalkali halide is very low and the quantity of compound required is small. The disks can easily be stored for reference puqx>ses or the compound can be recovered if required. 

A solution of iodine (1 equiv) in F.t20 is added slowly to a stirred suspension of the thallium salt of 1-cyclohexeneacctic acid (1 equiv) in dry Et20. The mixture is stirred for 1 h and the precipitate of thallium iodide is filtered off. The filtrate is washed with sat. aq sodium thiosulfate and sat. aq NaHC03 and then dried yield 40% ratio (3/2) 75 25. 

A) Dr. Honie Iron-based Sol System and (B) sodium and scandium iodides, sodium, thallium and indium iodides and dysprosium and thallium iodides lamps. Source Reproduced with permission from Honie UV America and the Atlas Electric Devices, Co. 

Gamma (y) Sodium iodide doped with thallium iodide are used pSlal(Tl)] thallium, which is present at 0.1-0.4% of sodium emits 420 nm scintillations. This phosphor is very efficient in absorbing y-radiation because of high atomic number of iodine and high density of sodium iodide. Sodium iodide is hermetically sealed. It is normally used in well counters. A typical well counter used in laboratory and that used in cameras in nuclear medicine are show in Figs. 3 and 4. 

In most instances, the peralkyls were the first to be isolated. This arose primarily from their volatility, which enabled easy separation from the nonvolatile solid residues. Thallium is one exception diethyl-thallium iodide was isolated in 1870, but the considerably less stable triethylthallium was not reported until 1930 118). 

J. Potassium iodoplatinate spray B Bi(N0373 - KI Reagent C uragendorff s Reagent D Thallium Iodide... 

Use Mixed crystals with thallium iodide for infrared radiation transmitters used in military detection devices. 

Synthesis of aromatic iodides. Treatment of an arylthallium ditrifluoroacetate with aqueous potassium iodide at room temperature results in rapid precipitation of thallium iodide and formation of the corresponding aromatic iodide in high yield 2... 

The photonitrozation reaction has a very low quantum yield ( 0.7). However, if 60 kW lamps doped with thallium iodide are used to produce an intense light emission at 535 nm (nanometers), while reducing the intensity of the other mercury bands, 24 kg/h of oxime can be produced per lamp, or about 180 t/year. The only industrial development of this process is that of Toray in Nagoya. The high consumption of electridty restricts it to areas where this type of energy is available cheaply.. 

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