Electronegativity and electron binding in gold alloys

Measurements were made of the Au core-electron binding-energy shifts which occur when Au metal is made the minor constituent in alloys of Pd, Pt, and Ni. These results and binding-energy shifts previously reported for alloys with Ag, Al, and Sn were combined with Mössbauer isomer-shift and work-function data to derive estimates for the net charging of the Au sites in these systems. Au turns out to be negative in all cases to the extent of $\sim 0.1e$, except for Au-Pt where the charging is less. Although considerably greater Au $s$ density increases are demonstrated by the Mössbauer data, they are largely compensated by depletion of the $d$ count. The trend in host-to-Au charge behavior is qualitatively in accord with the Pauling electronegativity scale.