Thallium halides, 377-8

Basically, when analysing the band structures, the equivalent observations apply to typical solid state compounds like thallium halides and lead chalcogenides. In studies on the origin of distortion in a-PbO, it was found that the classical theory of hybridization of the lead 6s and 6p orbitals is incorrect and that the lone pair is the result of the lead-oxygen interaction [44]. It was also noted... 

Thallous halides offer a unique possibility of studying the stereochemistry of the (chemically) inert electron pair, since their structures and their pressure and temperature-dependent phase transitions have been well established. Thallium (1) fluoride under ambient conditions, adopts an orthorhombic structure in the space group Pbcm which can be regarded as a distorted rocksalt structure (Fig. 2.4). In contrast to TIF, the thallium halides with heavier halogens, TlCl, TlBr and Til, adopt the highly symmetric cubic CsCl structure type under ambient conditions [46]. Both TlCl and TlBr, at lower temperatures, undergo phase transitions to the NaCl type of structure [47]. 

Thallium(I) acetate, 24 630-632 Thallium compounds, in organic reactions, 24 635 Thallium formate, 24 630 Thallium halides, 24 632 Thallium ion, 24 629 Thallium nitrate, uses for, 24 636 Thallium salts, 24 630, 632 Thallium sulfate, uses for, 24 636 Thallium (III) compounds, in organic reactions, 24 635-636 Thallium(III) fluoride, 24 632 Thallium(III) ion, 24 630 Thallium(III) salts, 24 632 Thallium(III) trifluoroacetate, 24 635 Thallium (Tl), 24 627-641... 

Thallium compounds, 24 629-635 properties of, 24 631t Thallium dichromate, 6 538 Thallium halides, uses for, 24 636 Thallium hydrides, 24 632 Thallium hydroxides, 24 632-633 Thallium intoxication, 24 638, 639... 

Thallium halides and a few other salts of thallium form addition compounds with ammonia. 

The physical properties of the thallium halides have been tabulated.1 Crystalline T1F has a distorted rock-salt lattice, with two independent thallium sites.333-335 The thermodynamic properties of the solid have been reassessed.336 At high temperature, the vapor phase contains TLF and T12F2 molecules,337 and matrix isolation studies have demonstrated the presence of both T1F and T12F2 in the solid the dimers have linear symmetry.338... 

The aqua ions, [M(H20)6]3+, exist in both aqueous solutions and crystalline salts [T1(H20)6]3+ has two trans H20 molecules that are more strongly bound than the others. Aqueous solutions of thallium halides also contain [T1X(H20)5]2+ and fra s-[TlX2(H20)4]+.8 The ions are acidic,... 

Silyl thallium halides (t-Bu3Si) TlX3 OC = halide, = 1,2) have been reported. These compounds display relatively low thermal stability. (t-Bu3Si)2TlCl has been obtained bv the addition of... 

Of the thallium halide complexes, the bromide complex is the most important in extraction separations. Tl(III) and Au(IlI) are extracted quantitatively from 1-3 M HBr with diethyl ether or DIPE, or MIBK. At that concentration of HBr, Fe(lII), Ga, In, Hg, and Te are extracted in small amounts. After extraction with MIBK, Ga, In, Fe(IlI), and Sn are stripped with a 1.5 iW HBr formamide solution, leaving only Tl(III) in the ketone phase [1]. The thallium(III) bromide eomplex has been extracted with TO A in benzene [2], or n-octylaniline in CHCI3 [3],... 

Salts of bivalent tin can also be used reaction of the dichloride or dibromide with dialkyl- or diaryl-thallium halides gives tin dihalides carrying two organic... 

A high permeability to infrared rays is achieved using crystals of thallium halides (combinations Tl(I)bromide/Tl(I)-iodide and Tl(I)-chloride/Tl(I)-bromide). 

Cyclopentadienylthallium is a superior reagent for many syntheses. It is easily prepared and stored, it may be handled in air, and the insolubility of thallium halide leads to high yields of product that may be filtered easily and worked up. The reagent has been used for preparing a variety of actinide, lanthanide, and transition metal cyclopentadiene complexes. 

In Table 24, the dissociation energies and wavelengths of the strongest absorption bands of the diatomic aluminium, gallium, indium, and thallium halides are given. Figure 99 shows the absorption spectra of AlCl and AlBr. 

Cyclopentadienylthallium is a light yellow solid that decomposes at 230°. It is stable for several months if stored under N2 in a Schlenk flask kept in the dark. Slow decomposition takes place in the air and light, whereupon the solid turns brown, but pure product may be sublimed away from this material. The IR spectrum shows absorption bands at 3022, 1584, 995, and 725 cm" Cycloi>entadienylthallium is insoluble in most organic solvents. It may be handled in air, and it is normally heated at reflux in THF solution with the substrate for about 2h under an inert gas atmosphere. When allowed to react with metal halides, the insoluble thallium halide produced may be filtered from the reaction solution. Most cyclopentadienyl complexes are air- and moisture-sensitive and should be handled with appropriate techniques. ... 

Thallium is also used in low-temperature thermometers, photoelectric cells, dye pigments, and to produce various types of resistant cements. Because of the element s high refractive index it is utilized in the manufacturing of optical lenses and imitation jewelry. Thallium is included as a component of corrosion-resistant alloys, organic reaction catalysts, and fireworks. The incorporation of thallium halides into organic alkylhalides produces formation of new complexes that act as phosphors. This is the basis for using thallium in scintillation counters [Nal(Tl)]. 

A phenomenon of great practical relevance is the increase of ion conductivity by adding second surface active particles (a). The earliest example was LiI Al203, [11] later examples are silver, copper, and thallium halides which showed similar effects [4, 5]. Similar effects can also be observed for anion conductors examples (e.g., PbF2 Si02) (b) [4]. They all find their explanation in the concept of... 

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