| dc.description |
Gold-197 Mössbauer parameters are reported for the salts Z[AuR2]{R = C6F5, Z =[NBu4]<sup>+</sup>, [Ag(C4H8S)]<sup>+</sup>, [Au(SbPh3)4]<sup>+</sup>, or [Au(pdma)2]<sup>+</sup>[pdma =o-phenylenebis(dimethylarsine)]; R = C6F3H2, Z =[NBu4]<sup>+</sup>, Ag<sup>+</sup>, or [Ag(C4H8S)]<sup>+</sup>}. For salts of the same cation, the isomer shift and quadrupole splitting are both slightly smaller for R = C6F5 than for R = C6F3H2, in accord with the electronegativities of the aryl groups. For each anion, the parameters decrease in the order Z =[NBu4]<sup>+</sup> > [Ag(C4H8S)]<sup>+</sup> > Ag<sup>+</sup>; this trend probably indicates increasing interionic association. The data for the two gold-containing cations are consistent with four co-ordination; the lower symmetry of [Au(pdma)2]<sup>+</sup> is revealed by a small quadrupole splitting. These cations give more intense spectra than the anions, consistent with dependence of the recoil-free fraction on ionic mass. |
