Gold ionic

Along with metals, the threshold of forced cold brittleness is also observed in solids of all other kinds, that is, covalent crystals (e.g., in the system germanium-gold), ionic substances (e.g., sodium chloride in the melted aluminum chloride), and molecular crystals (e.g., naphthalene in liquid hydrocarbon). In the other words, there is only a limited interval of optimum temperatures in which the Rehbinder effect is observed. At temperatures that are too low, the effect is retarded by the excessive starting brittleness and the solidification of the medium, while at temperatures that are too high, it is retarded by the excessive plasticity of the solid. This temperature dependence is one of the principal features of the Rehbinder effect, which makes it very different from the chanical or corrosive action of the medium, both of which intensify as temperature increases. 

Use of thiazolium-gold ionic iiquid as cataiyst for the hydration of phenyiacetyiene... 

Deetlefs et al. have used the thiazolium-gold ionic liquids for the catalytic hydration of phenyiacetyiene to acetophenone using imidazolium ionic liquids as the reaction media. 

Gore TR, Bond T, Zhang WB, Scott RWJ, Burgess IJ (2010) Hysteresis in the measurement of double-layer capacitance at the gold-ionic liquid interface. Electrochem Commun 12(10) 1340-1343. doi 10.1016/j.elecom.2010.07.015... 

The exact value of the standard potential of the Au(l)/Au and Au(lll)/Au couples is of little practical significance what is important is the instability of the ionic state in aqueous solutions and the need to stabilize the gold ionic species through complexation. 

Germanium In situ STM studies on Ge electrodeposition on gold from an ionic liquid have quite recently been started at our institute [59, 60]. In these studies we used dry [BMIM][PF<3] as a solvent and dissolved Gel4 at estimated concentrations of 0.1-1 mmol 1 the substrate being Au(lll). This ionic liquid has, in its dry state, an electrochemical window of a little more than 4 V on gold, and the bulk deposition of Ge started several hundreds of mV positive from the solvent decomposition. Furthermore, distinct underpotential phenomena were observed. Some insight into the nanoscale processes at the electrode surface is given in Section 6.2.2.3. 

Only AuF of the gold(I) halides is unknown in the solid state its stability can be examined by means of a Bom-Haber cycle, assuming that it would have an ionic lattice like AgF. (AuF has been generated in the gas phase from Au+ and CH3COF [22].)... 

The soft Au+ forms relatively few complexes compared with those of phosphines. Complexes with ammines, nitriles and diazoles like Au(NH3)2 and Au(RCN)2 are known but little studied. In linear Au(NH3)2, Au-N is 2.01-2.03 A [70a], [Au(NCPh)2]+ has been used as a labile source of other gold complexes [70b]. AuCl(piperidine) is a monomer with weak tetra-meric association in contrast AuX(py) (X = Cl, Br, I) are [Aupy2]+[AuX2] with a chain structure in the solid state (and Au-Au interactions), suggesting a close balance between factors for molecular and ionic structures [70c] (note also the tetrahydrothiophene complexes in section 4.10.6). 

The preference of gold(III) for planar 4-coordination is such that ligands sometimes adopt unusual denticities. Therefore, Au(N03)J has four mono-dentate nitrates Au(terpy)Cl3.H20 contains Au(terpy)Cl2+ Aupy2Cl3 is Aupy2Cl2 CP Au(S2CNBu2)2Br is Au(S2CNBu2)2 Br- Au(S2CNBu2)3 has one bidentate and two monodentate dithiocarbamates and Au(NH3)4(N03)3 has only ionic nitrates, to quote compounds already mentioned. 

Figure 13. Schematic diagram of the measurement of the ionic conductivity of a conducting polymer membrane as a function of oxidation state (potential), (a) Pt electrodes (b) potentiostat (c) gold minigrid (d) polymer film (e) electrolyte solution (0 dc or ac resistance measurement.133 (Reprinted with permission from J. Am Chem Soc. 104, 6139-6140, 1982. Copyright 1982, American Chemical Society.)...

Classify each of the following solids as ionic, network, metallic, or molecular (a) iron pyritc (fool s gold), FeS, ... 

Furthermore, the reaction scheme implies that the molecular weight distribution is Poisson-like — i.e. very narrow — as it had been shown earlier on theoretical basis by Flory 8), Gold 9), and Szwarc l0>. Even though two (or more) types of active species add monomer at very different rates, the polydispersity remains narrow, provided solvation/desolvation and ionic dissociation/association processes are fast U). 

The compound CsAu is ionic, Cs Au RbAu was also thought to be ionic owing to xs Rb in the lattice but is now thought of as being a semiconductor. The preparation of CsAu is from a gold film with Cs vapor. The gold film is first... 

An interesting intermetallic gold compound is CsAu, where Au is bound to the most electropositive metal Cs (Xcs = 1-2). As a result we obtain an ionic bonding situation for the semiconductor Cs Au and not a metallic bond as one expects (two metals do not necessarily form a metallic bond ). Figure 4.12 nicely shows that the HOMO consists mainly of Au(6s) with much smaller Cs(6s) and Au(dn) participation, while the LUMO is mainly Cs(6s). Saue and co-workers calculated relativistic... 

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