Halides fluid phase

Marsh, K.N., Boxall, J.A. lichtenthaler, R. (2004). Room Temperature Ionic Liquids and Their Mixtures, a Review, Fluid Phase EquUtb., pp. 219, 93-98 Mathews, C.J., Smith, P.J. Welton, T. (2000). Palladium Catalysed Suzuki Cross-Coupling Reactions in Ambient Temperature Ionic Liquids, Chem. Commun., 14, pp. 1249-1250 McNulty, J., Capretta, A., Wilson, J., Dyck, J., Adjabeng, G. Robertson, A. (2002). Suzuki Cross-Coupling Reactions of Aryl Halides in Phosphonium Salt Ionic Liquid imder Mild Conditions, Chem, Commun., 17, pp. 1986-1987 McLachlan, F., Mathews, C.J., Smith, P.J. Welton, T. (2003). Palladium-Catalyzed Suzuki Cross-Coupling Reactions in Ambient Temperature Ionic Liquids Evidence for the Importance of Palladium Imidazolylidene Complexes, Organometallics, 22, pp. 5350-5357... 

The aqueous fluids formed by melting of ices in asteroids reacted with minerals to produce a host of secondary phases. Laboratory studies provide information on the identities of these phases. They include hydrated minerals such as serpentines and clays, as well as a variety of carbonates, sulfates, oxides, sulfides, halides, and oxy-hydroxides, some of which are pictured in Figure 12.15. The alteration minerals in carbonaceous chondrites have been discussed extensively in the literature (Zolensky and McSween, 1988 Buseck and Hua, 1993 Brearley, 2004) and were most recently reviewed by Brearley (2006). In the case of Cl chondrites, the alteration is pervasive and almost no unaltered minerals remain. CM chondrites contain mixtures of heavily altered and partially altered materials. In CR2 and CV3oxb chondrites, matrix minerals have been moderately altered and chondrules show some effects of aqueous alteration. For other chondrite groups such as CO and LL3.0-3.1, the alteration is subtle and secondary minerals are uncommon. In some CV chondrites, a later thermal metamorphic overprint has dehydrated serpentine to form olivine. 

The directors (long molecular axes) of the constituent molecules in nematic phases are parallel to one another on average. This is the only order present in nematic liquid crystals, which are the most fluid type of liquid-crystalline phase. Molecules that form cholesteric phases must be optically active or contain an optically active dopant. As the phase name implies, the constituent molecules are frequently steroids and most commonly are cholesteric esters or halides. A conceptual model of the cholesteric phase includes layers of molecules in nematic-like positions, each layer being twisted slightly with respect to the ones above and below it. When the phase consists only of optically active molecules, the angle of twist between layers is typically less than one degree. Several subclasses of discotic phases exist. In all, the molecular planes of the constituent molecules are parallel. However, the discs can pack in nematic-like arrangements (ND) or in columns that are internally ordered (D ) or disordered (Dd) and may be stacked vertically,... 

In addition to the tetraethyl or tetramethyl lead, both types of antiknock fluids also contained 1,2-dichloroethane and 1,2-dibromoethane (ca. 35% by weight) to react with the lead released on combustion to form lead bromide and lead chloride. These lead halides are volatile at the cylinder combustion temperatures of 800-900°C, and leave the combustion chamber with the exhaust, which prevented the buildup of lead deposits. This was also the final step in the chain of events occurring with the alkylated lead antiknock compounds, which contributed to the widespread dispersal of lead compounds to the air and soil wherever gasoline powered vehicles operated. For this reason, and the toxic exposures during refueling, the alkylated lead addition rate was reduced to not more than 0.5 g of contained lead per U.S. gallon by 1980, even for leaded gasolines [29], and was phased out in the U.S. and Canada by 1985. 

In the 1960s, there was already a forerunner of photochemically induced phase transition in LC (20). When mixtures of cholesteryl iodide and cholesteryl bromide with cholesteryl nonanoate were exposed to UV irradiation, the helical pitch of cholesteric LC changes as a result of photodecomposition of the halides. The reflected color shifts gradually to red with progression of photodecomposition. Pattern-wise imaging was demonstrated but the image was blurred within 15 min. since LC of small molecules is a viscous fluid. 

The observation of electric transport in dense supercritical ionic phases stimulated the investigation of conductance in supercritical metals above 1500 °C and to pressures of about 2000 bar. The conductance of mercury was investigated and continuous metal-nonmetal transition was observed [25]. An impressive amount of further aspects of such metal-nonmetal transitions has been studied later in alkali metals and other fluids (see F. Hensel and coworkers) [25a]. A metal-nonmetal transition was also observed in cesium hydride and cesium in the liquid state at high hydrogen pressures [26] which corresponds to the earlier non-pressure work of Max Bredig [26a] with liquid metal-metal halide systems. 

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