The atomic dynamics of the liquid binary system RbxSb1-x has been studied at different concentrations by cold neutron inelastic scattering. The variation of the atomic interactions by changing the composition is reflected in the dynamic behaviour. The dispersion obtained from the longitudinal current correlation function Jl(Q,ω) shows a shift to larger Q and higher frequencies with increasing Sb concentration. This indication of stronger bonds towards the ionic and partly covalent regime can also be observed in the frequency spectrum z(ω). At equiatomic composition a second band can be found in z(ω) at higher frequencies.