Global potential energy surfaces (PESs) of SiCN/SiNC in the (X) over tilde (2)Pi (A' and A '') electronic state have been determined from MRCISD/aug-cc-pVTZ computations. Although spin-orbit coupling with lower-lying quartet states has a maximum of 3.4 cm (1) near linear SiCN, it is found to be negligible for bending form. Vibrational energies with J = 0 and 1 were computed up to 360 levels by quantum vibrational calculations using the three-dimensional PESs of the lowest (2)A' and (2)A '' states. The Renner parameters for the linear SiCN and SiNC estimated from the lowest bending level are 0.300 and 0.283, respectively. (C) 2011 Elsevier B. V. All rights reserved.