We studied the surface structures of the cubic SiC nanocrystals by use of infrared spectroscopy. It was found that the Si-Si surface reconstruction occurs significantly in these nanocrystals. Besides, the oxygen bridge bond dominates their surface structure, which ensures the occurrence of ultra stable quantum-confinement photoluminescence. The larger crystallites exhibit much weaker infrared signals, but show longitudinal phonon mode that is absent in the small particles. The nanocrystals dispersed in lower-polarity solvent exhibit additional surface bonding structure other than that in water solvent. (C) 2011 Elsevier B.V. All rights reserved.