Low-energy loss spectra (LELS) from electron energy loss spectroscopy (EELS) in a transmission electron microscope do not yield structural information as readily as do core loss spectra. In order to make LELS a more general technique, we have studied the 10--15 eV energy range in some $M{\mathrm{O}}_{2}$ compounds in great detail and identified a characteristic peak of a specific structural unit. A comparison of experimental EELS spectra and ab initio density-functional theory calculations (WIEN2K code) is presented. A definite peak around 14 eV appears in the imaginary part of the dielectric functions of those structures containing rutile units. These rutile units are ${M}_{3}{\mathrm{O}}_{15}$ clusters made of edge- and corner-sharing octahedra, which when stacked lead to rutile structures, among others. The peak is present in rutile phases with $M=\mathrm{Ti},$ V, Cr, Mn, Si, Ge, Sn, and Pb. Other structures, such as Ramsdellite or high-pressure ${\mathrm{TiO}}_{2}$ phases, also contain the necessary structural unit and indeed present the same feature. The origin of the peak can be elucidated by means of band structure calculations and an analysis of the orbitals involved in the transition. The existence of such a peak, always visible around 14 eV whatever $M,$ shows its remarkable universality.