Anion in salts

The far IR spectra of the [Znd4]2- anion in salts with the 1,10-phenanthrolinium and 2,2-bipyridinium cations have been reported.1039 The anion in the former salt appears to be tetrahedral, while that in the latter is believed to be halogen-bridged. 

Interestingly, for these compounds simple halide ions constitute the counter anion in salt formation. The compactness of the ring, especially in the case of L3, does impose a severe steric constriction at the metal centre. In the case of uncomplexed L2 the preferred endodentate conformation identifies it as an (almost) ideal ligand for occupation of three metal coordination sites (fac-octahedral)16-20. For free L3 there are four chair conformers... 

Unlike chloride 80, the Sn atom in the mono(dithiolato) tin complex 81 is displaced from the equatorial plane toward the axial S atom (but not the axial chlorine). The anion in salt 82 adopts distorted TBP structure with equatorial methyl groups and a long axial Sn—Cl bond (2.652 A). 

In most cases the structure given is inferred from the structure of anions in salts of the acids. Free add unknown. 

Metals. These are similar to ionic solids, since they contain a lattice of positively charged metal cations. The anions are electrons which differ from anions in salts like NaCl by being mobile. The mobility of the electrons in metals permits metal surfaces to act as very active centers for both free radical and ionic reactions. 

Wieland, 1907 Wieland and Wecker, 1910). Oxidation was carried out in an inert solvent such as benzene, from which the salt precipitated. The easier and more reliable preparation of perchlorate salts by the iodine-silver perchlorate method (Weitz and Schwechten, 1926, 1927), to which we have referred earlier (p. 168), allowed a much clearer understanding of the nature of triarylaminium ions to be obtained. Isolation of perchlorates permitted chemical studies, and easy reduction to the triarylamine by iodide ion, ferrous ion, etc., was consistent with the cation-radical view that was developed. The name aminium ion was coined by Weitz. Other salts were prepared such as tritolylaminium picrate (by oxidation of the amine with lead dioxide in the presence of picric acid), and it was also recognized that conjugate anions in salts obtained by oxidation with antimony pentachloride, phosphorus pentachloride and ferric chloride had to be complex anions rather than simple anionic radicals. This is a particularly pertinent point in antimony pentachloride oxidations (p. 165). 

Figure 5 Dicarbollide derivatives used as anions in salt partitioning and cation exchange. The numbering scheme was taken from [210]. Formulas of the anions and names of the bridging groups were taken from [201] except for -phenylcne, the exact isomeric form of the bridging groups could not be determined from this reference or references cited therein. The structure of the unsubstituted anion DCC I is correct as shown when a bridging group is present, the carbon atoms in the hemispheres are constrained to the same side of the molecule.

Bostrom et al. emphasized the importance of dispersion forces regarding the specific ion effects on proteins and also regarding non protein-related Hofmeister effects. The charge on the protein lysozyme depends on the anion in salt solutions (Bostrom et al. 2003a), but only Cl and SCN (as their potassium salts) are compared. Phos-phatidylglycerol bilayers (Bostrom et al. 2006a) are affected by Cl , Br , and SCN (as their sodium salts) in this order. Even silica membranes show Hofmeister series effects, namely in pH measurements with a glass electrode in fairly concentrated... 

---