The energies of the 2p1/2, 2p3/2, 3s, 3p1/2, 3p3/2, and 3d3/2,5/2 photopeaks and of the L2,3M4,5M4,5 Auger peaks have been measured for arsenic metal and 19 of its compounds. By comparing the photopeak and Auger chemical shifts, the changes in the total (static) relaxation energies were determined. It was found that the relaxation energy change provides a useful parameter for characterizing nearest neighbor groups and that electronegativities derived from them offer the advantages that they are independent of the energy reference level and of charging effects.