Until now, oxide precipitation has been treated in theoretical models as homogeneous nucleation of incoherent SiOx precipitates. In view of the higher interface energy of an incoherent precipitate, one should also consider the possibility of having coherent precipitation. The key role of VO2 complexes for nucleation of oxide precipitates has already been demonstrated on a broad experimental basis. Ab initio calculations have shown that the agglomeration of VO2 is energetically favorable. In this contribution, the bulk modulus and molecular volume of nVO(2) clusters, named here seed-SiO2, are determined and an analytical nucleation model is developed. In a second step, a more advanced model is developed based on a monolayered agglomeration of VO2 complexes on {100} planes, named here seed-SiO, and the heterogeneous nucleation of amorphous SiO2 (a-SiO2) at these plates. The advanced model is regarded as the more plausible nucleation path because the free energy is decreased stepwise. (c) 2008 The Electrochemical Society.