The structures in the total kinetic energy (TKE) distributions in cold fission of234U and236U are interpreted in terms of the Coulomb interaction energy (C) between fragments at the scission point. The maximal value of C, Cmax, corresponding to the most compact scission configuration, is calculated for several mass fragmentations. It is shown that with Q being constant, Cmax increases if one increases the charge asymmetry for a given primary fragmentation. This condition produces oscillations with a period of approximately 5 amu of Cmax as a function of the light fragment mass which are correlated with the observed oscillations of the maximal value of TKE. Moreover, the enhancement of the yields of the more asymmetric charge fragmentation for a given fragmentation is explained. © 1986 Springer-Verlag.