DFT calculations are applied to devise highly doped T-h symmetry C36X24 ( X = Si, B, Al, N, and P) heterofullerenes where the dopants are completely isolated from each other by means of strong C=C double bonds. Vibrational analysis shows that except C36Al24 all other heterofullerenes are true minima. Isolating the dopants is an applicable strategy for obtaining highly doped stable heterofullerenes since it avoids weak hetero-hetero bonds. (C) 2011 Elsevier B.V. All rights reserved.