Known processes for the production of nanoparticles of compounds of the transition metals Zr, Ti, Ta, rare earths (RE), Mn, and Fe via microemulsions lead to products that contain impurities from the reactants, particularly water, which make the further use of said nanoparticles difficult, for instance in high-temperature super conductors (HTSC). It is proposed that the nanoparticles be produced via anhydrous microemulsions having an outer phase composed of a nonpolar solvent and inner phase composed of a polar anhydrous solvent. The nanoparticles thus obtained exhibit good monodispersity and can be used in the production of REBa2Cu3O7 super conductors by incorporation into the precursor coating solution.