The standard heat of formation (Delta H-f degrees) of corannulene (C20H10) is calculated based on 40 hyperhomodesmotic reactions and compared with the existing experimental result. We found that: (1) the reliability of hyperhomodesmotic reactions depends on the construction scheme and the reference molecules; (2) both resonance energy and nonplanar strain energy should be considered during the construction of hyperhomodesmotic reactions. Two principles are proposed for the selection of reference molecules: (i) structurally similar to the object molecule; (ii) simple and small. Due to structural similarity, the above knowledge obtained from C20H10 is of great reference for polycyclic aromatic hydrocarbons and fullerenes. (c) 2006 Elsevier B.V. All rights reserved.