Rhenium-doped silicon samples had been synthesized by means of re-pulsed ion implantation (fluences 2.5 x 10(17) cm(-2), 1 x 10(17) cm(-2)and 5 x 10(16) cm(-2)) and then stored under natural air-media conditions 5 years. The electronic structure of these samples was studied using combined XPS-and-DFT method. It was confidently established and demonstrated by means of XPS electronic structure mapping (core levels, valence band) that weak acidification occurs. The influence of air media leads to O horizontal ellipsis Si-O horizontal ellipsis [Re-0] and horizontal ellipsis Re-Si-O horizontal ellipsis bonding appearance in the structure of 5-year aged samples rather than to normal rhenium oxidation. No any traces of Re(x)O(y)sub-oxide fractures were neither found experimentally nor predicted theoretically. DFT-derived acidification scenario points out energetically preferable Re atoms pairing when low concentrations ion-doping regime is applied and metallic Re clusterization in the high concentrations ion-doping regime. Experimentally established essential transformation of initial vicinity states in the top of valence bands by means of Re 5ddoping is in a good agreement with DFT calculations of electronic structure and formation energy values of acidification process.