Halogen halogenides

Table 3-2.—Bond Energies fob Hydrogen Halogenide and Halogen Halogenide Molecules (Kcal/Mole)...

Halogen-carbonsaure-halogenide werden i. a. durch das elektrophile Lithiumala-nat/Aluminiumchlorid mit besseren Ausbeuten reduziert als mit Lithiumalanat, zudem hangen die Ausbeuten nicht von der Zugabemethode ab4 5. 

Auch Briickenkopf-Halogen-Atome sowie Halogen-aromaten, Vinyl-halogenide usw. werden mit uberschiissigem Lithiumalanat bei geniigend hohen Reaktionstemperaturen zu Kohlenwasserstoffen reduziert4. 

In the CeSI (115) and NdSBr (334) type of structure, bromine and iodine are coordinated to five metal ions (four of the same layer, and one of the opposite layer) and four halogen ions of the double layer. In the SmSI type (335), iodine is coordinated to three metal ions of a [LS] layer and three other iodine ions of the double layer. In the FeOCl type of compound, such as ErSCl (355) and LuSBr (85), the halogen is surrounded by a polyhedron formed by six sulfur and four halogenide ions. 

Halogen content If halogens in the anion are not crucial for specific reactions performed in the ionic liquid, they should be avoided. Moisture sensitivity, halogenide transfers, alcoholysis and toxic effects are often connected with halogen atoms in the molecule [27]. In addition, the hydrolysis products HCl or HF act corrosively. Within the project reported by Wasserscheid and coworkers they successfully developed ionic liquids with alkylsulfate groups as anions to overcome the halogen content. These new solvents show very favorable properties. 

A few years ago experimental values were available for Q, S, /, and Z), but not for E the procedure adopted in testing the equation was to use the equation with calculated values of Uq (Equation 13-5) to find E, and as a test of the method to examine the constancy of E for a series of alkali halogenides containing the same halogen. The values obtained in this way were found to be constant to within about 3 kcal/mole. However, later experimental determinations of the values of the electron affinities of the halogen atoms by direct methods have shown that Equation 13-5 for the crystal energy is in general reliable only to about 2 percent. 

Work on the direct determination of the electron affinities of halogen atoms was begun by Mayer,7 who, with his students, measured directly the equilibrium constant for dissociation of alkali halogenide gas molecules into ions or of gas halogenide ions into atoms and electrons. Other methods have also been used, especially some involving mass... 

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