Iodides metals

Although some of the more volatile metal iodides have been used as precursors in the CVD of metals and metal oxides [10], reports on the preparation of metal iodides by CVD are sparse. Copper iodide has been prepared by laser-assisted molecular beam deposition [11] and vapor phase electrolytic deposition has been used for the preparation of silver iodide [12]. 

Metal oxides display a variety of unique physical and chemical properties and are employed in numerous technological applications (Table 7-1). Chemical vapor deposition has been used widely for the preparation of metal oxide thin films [10, 13]. The following section summarizes the preparation of several transition metal and main group element oxides by CVD. 

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Charge-Transfer Salts. Most charge-transfer salts can be prepared by direct mixing of donors and acceptors in solution. Semiconducting salts of TCNQ have been prepared with a variety of both organic and inorganic counterions. Simple salts of the type TCNQ can be obtained by direct reaction of a metal such as copper or silver with TCNQ in solution. Solutions of metal iodides can be used in place of the metals, and precipitation of the TCNQ salt occur direcdy (24). 

Solutions of alkah metal and ammonium iodides in Hquid iodine are good conductors of electricity, comparable to fused salts and aqueous solutions of strong acids. The Hquid is therefore a polar solvent of considerable ionising power, whereas its own electrical conductivity suggests that it is appreciably ionized, probably into I" and I (triodide). Iodine resembles water in this respect. The metal iodides and polyiodides are bases, whereas the iodine haHdes are acids. 

Moist iodine vapor rapidly corrodes metals, including most stainless steels. The initial process is the formation of corrosion centers where small amounts of metal iodide are formed which deHquesce, and the corrosion then takes place electrochemically (41,42). Only titanium and molybdenum steels are unattacked by iodine (42,43). The corrosion of molten iodine has also been studied. 

R. E. Rolsten, Iodide Metals and Metal Iodides, John Wiley Sons, Inc., New York, 1961. 

Lead Iodide. Lead diiodide, Pbl2, forms a powder of yellow hexagonal crystals some physical properties are given in Table 1. Lead diiodide is soluble in alkaUes and potassium iodide, and insoluble in alcohol. It is made by treating a water-soluble lead compound with hydroiodic acid or a soluble metal iodide. It is readily purified by recrystaUization in water. 

Bulk production of United States Pharmacopeia (USP) and reagent grades is based on the reaction of sodium carbonate or hydroxide with an acidic iodide solution, typically hydriodic acid or a metal iodide. After removal of chemical impurities, the solution is filtered and concentrated. Evaporation gives the anhydrous Nal. Controlled cool-down produces either the dihydrate or the pentahydrate [81626-33-7]. 

Certain metal iodides, eg, sodium, potassium, cesium, or mbidium, react with sulfamic acid to form the corresponding alkah metal triodides (17) ... 

Metal halides can in some cases, be used to replace other atoms or groups besides fluorine with halogen Polyfluoroacyl fluorides and chlorides can be converted to fluoroalkyl iodides by simply heating the reactant in the presence of an alkali metal iodide [[Pg.382]

CI2 into alkaline solutions of Br ). lodates can be prepared either by direct high-pressure oxidation of alkali metal iodides with oxygen at 600° or by oxidation of I2 with chlorates ... 

Deb [1238] prepared thin films of inorganic azides (for optical studies) by reaction of an alkali metal azide with a heavy metal iodide, e.g. 

Almost all of the rare-earth metal/rare-earth metal tri-iodide systems, R/RI3, contain binary phases with the rare-earth element in an oxidation state lower than -1-3 ( reduced rare-earth metal iodides) [3, 7, 10-13]. More common is the oxidation state -i-2. Elements that form di-iodides RI2 are illustrated in Fig. 4.1. 

Finally, metal iodides react violently with diphosphorus pentoxide. 

Karayannis NM, Mikulski CM, Strocko MJ, et al. 1971b. Reactions of alkali metal iodides with diisopropyl methylphosphonate. Inorg Chim Acta 5(3) 357-361. 

Hexafluororhenate(V) salts are obtained by the interaction of the appropriate alkali metal iodide with ReFg in either SO 2 or IF5 (57). For most cations the magnetic moments lie between about 1.3 and 1.4 B.M. at 298 °K, slightly higher results being found for the potassium salt (39). 

Biopsy specimens were immersed in a solution of 0s04-ZnI2. The ZIO mixture was prepared as follows 5 g of metallic iodide was mixed with 10-15 g of zinc metal. The combined powders were dissolved in 200 mL of distilled water. Eight milliliters of the filtered solution was combined with 2 mL of unbuffered 2% 0s04 The biopsy specimens were immersed in the ZIO solution for 24 h at room temperature in the dark. 

The redox equilibria can be considerably shifted by the presence of additional donor units. Thus the redox potential in a donor solvent will be influenced by the presence of anions and it may be different for a metal chloride and a metal iodide. The effect becomes more pronounced if the supporting electrolyte contains anions which have donor properties. Such donor anions will compete with solvent molecules for coordination. 

In 1986, BP Chemicals became the owners of the Monsanto technology. They subsequently also developed their own Cativa process, aimounced in 1996, carbonylation of MeOH to AcOH catalysed by Ir and Mel and promoted with specific metal iodides [8]. As with the improvements in the original Monsanto Rh process, Cativa had benefits such as improved catalyst stability and more favorable operating conditions [9]. 

Le Roux C, Gaspard-Iloughmane H, Dubac J, Jaud J, Vignaux P (1993) New effective catalysts for Mukaiyama-aldol and -Michael reactions bismuth trichloride-metallic iodide systems. J Org Chem 58 1835-1839... 

Reactions with metals in a finely-divided state or at elevated temperatures, produce metal chlorides and metal iodides ... 

Yellow hexagonal crystals density 6.16 g/cm melts at 402°C vaporizes at 954°C decomposes at 180°C when exposed to green light slightly soluble in water (0.44 g/L at 0°C and 0.63 g/L at 20°C) Ksp 8.49xlCL9 at 25°C partially soluble in boiling water (4.1 g/L at 100°C) insoluble in ethanol soluble in alkalis and alkali metal iodide solutions. 

In general, mercury(II) iodide forms neutral complexes of compositions M2(Hgl4) and MfHgls) with alkali and alkaline metal iodides. 

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