The MSssbauer isomer shift provides a direct measure, sampled at the nucleus, of charge flow on or off an atomic site in a solid. Isomer shift data exist for a variety of nuclei as impurities in alloys, and while comparisons have been made with electronegativity scales, no universal correlation has emerged. 1 In this paper, we will show that, once volume effects are suitably accounted for, the isomer shifts of 57Fe, 99Ru, 181Ta, 1931r, 195pt and 197Au display common behavior. These are the only transition metals for which there are sufficient data of sufficient resolution to be considered. In addition to volume effects, factors contribute to the contact density at a transition metal nucleus and hence to the isomer shift, upon alloying. First there may be an increase or decrease in d electron count, Ana, a[ the impurity site. The d electrons have no density at the nucleus but, b9 screening the s-p conduction electrons, an increase in d count produces a decrease in the contact charge density. Secondly, there may be a change in the non-d conduction electron count, An c. As a result, the volume-corrected isomer shift for some given nucleus becomes AS(vol.corr.) ~ AS - dV AV = C n e - RAn (i) where C and R are constants and V is the atomic volume. Given the minus sign inside the bracket, R is positive and calculation suggests it is the order of 1/2 to i. In other words, d and non-d terms oppose one another and are of the same order. We have already noted that the AS(vol.corr.),for the six elements in question, will display common behavior. What is more, comparison with electronegativity scales, which are associated with the sum of An d and Anr will suggest that the ratio of And/An c is a constant. Non-d an-d-d charge flow in opposite directions upon alloying, and, to a remarkable extent, the ratio of these two terms is a constant independent of impurity atom and independent of the host in which the impurity finds itself. Making the volume correction involves obtaining the derivative and choosing the impurity volume. For Fe, Ta and Au there are experimental data on the effect of pressure, hence of volume, on AS. Now