Gold-silver distance

The atomic 8u rangements and bonds of the gold-silver ditellurides. Acta Cryst. 5 (1952) 375—381. (George Tunell and Linus Pauling). Interatomic distances and atomic valences in NaZnia. Acta Cryst. 5 (1952) 637—644. (David P. Shoemaker, Richard E. Marsh, Fred J. Ewing, and Linus Pauling). SP 54 ... 

Equations (11a) and (12a) are based upon the values 1-399 and 1-430 for R sp3) for tin and lead, respectively, with slopes as indicated by the tetrahedral radii for the heavier elements. The value 1-430 for quadrivalent lead was obtained by adding to the radius for quadrivalent tin the difference 0-031A between the Mg-Pb distance in Mg2Pb and the Mg-Sn distance in Mg2Sn. The simple form of equations (116) and (126) was assumed in analogy with (106), and the equal values of the constant were obtained from the observed distances for silver and gold, both assumed to have valence 5 . 

Theoretical studies by Pyykkb in 1998 for [M2(NHCHNH)2] systems, M=Cu, Ag, and Au, predicted the M-M distances at the MP2 level [8]. Experimentally, systems containing amidinate ligands were known with Cu and Ag but unknown with Au. The results for the models containing silver and copper are close to the X-ray structures of [M2(ArNC(H)NAr)2], Ar=C6H4-4-Me and M=Ag, Cu. The Ag-Ag distance is 2.705 and 2.712 A and the Cu-Cu distance is 2.497 and 2.528 A at the experimental and theoretical level. Table 1.1. The hypothetical dinuclear gold(I) amidinate compound was calculated to have an Au-Au distance at the MP2 level of 2.728 A [8]. The dinuclear gold(I) amidinate complex now known proves the predicted Au-Au distance to be rather good. 

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