Halide complexes 5 state

Rhenium Halides and Halide Complexes. Rhenium reacts with chlorine at ca 600°C to produce rheniumpentachloride [39368-69-9], Re2Cl2Q, a volatile species that is dimeric via bridging hahde groups. Rhenium reacts with elemental bromine in a similar fashion, but the metal is unreactive toward iodine. The compounds ReCl, ReBr [36753-03-4], and Rel [59301-47-2] can be prepared by careful evaporation of a solution of HReO and HX. Substantiation in a modem laboratory would be desirable. Lower oxidation state hahdes (Re X ) are also prepared from the pentavalent or tetravalent compounds by thermal decomposition or chemical reduction. 

Halide complex ions of ruthenium and osmium in the +3 state are known for all except OsFg" [39], Syntheses include ... 

Ethylenediamine complexes Extraction Halide complexes structures vibrational spectra Halides +3 state +4 state +5 state +6 state... 

The aqua ion Au(H20)4+ has not been characterized either in solution or in the solid state. Most of the substitution studies have involved the halide complexes AuXj and Au(NH3) (Ref. 319). A number of earUer generalizations have been confirmed. Rates are very sensitive to the nature of both entering and leaving ligands and bond formation and breaking are nearly synchronous. The double-humped energy profiles witnessed with Pd(II) and Pt(II) are not invoked the five-coordinate species resulting from an associative mechanism is the transition state ... 

Most alkenes, however, react via a transition state that involves the alkene, hydrogen halide, and a third species which delivers the nucleophile. This termolecular mechanism is generally pictured as a nucleophilic attack on the alkene-hydrogen halide complex. This... 

A large number of halide complexes of thallium(III) have been prepared by precipitation of the complexes from solution with a suitable cation, eg, H+, (C2H5)4N+, (C6H5)4As+, and K+. Both four-coordinated [HXJ" and six-coordinated [TlXJ3 ions exist in solutions and in solid states. 

The nickel halide complexes of Schiff bases (113) and (114) obtained from benzaldehyde and a number of diamines have the formula NiX2L (X = Cl, Br, I) with pseudotetrahedral structure in the solid state and in solution as well.954... 

High oxidation state silver halide complexes of chloride, bromide and iodide tend to be even more unstable with respect to reduction and have not been studied in detail.549... 

Following the preparation of 4.79, a number of other cyclic mercury crown compounds have been synthesised, which do exhibit halide complexation behaviour. Compound 4.80, forms a 1 1 polymer with bromide in the solid state in which the Hr anions perch above the Hg3 plane. The Hg—Br distances of 3.07-3.39A are considerably longer than normal Hg—Br covalent bonds (about 2.54A).61 The compound also binds SCN- with similarly long bonds as shown in Figure 4.34.60 The analogous chloride complex has a 3 2 stoichiometry suggesting a triple-decker sandwich of type [4.80 Cl 4.80 Cl 4.80]2. ... 

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