Structural and anharmonic spectroscopic properties of SiC4 are investigated using the RCCSD(T)-F12 method and second order perturbation theory. Observable parameters are determined for various isotopomers, (SiC4)-Si-28-C-12, (SiCCCC)-Si-28-C-13, (SiCCCC)-Si-28-C-13, (SiCC)-Si-28 (CC)-C-13, (SiCCC)-Si-28 C-13 and (SiC4)-Si-29. Fermi interactions are considered in the model. Results are compared with the parameters of C-5. For (SiC4)-Si-28-C-12, the v(1) fundamental has been found at 2094 cm (1) with RCCSD(T)-F12, close to the observed value 2095.46 cm (1). In addition, B-0 has been determined to be 1536.29 MHz with RCCSD(T)/CBS, whereas the experimental value is 1533.8 MHz. The CASSCF/aug-cc-pVTZ equilibrium dipole moment was estimated to be 6.2112 Debyes. (C) 2010 Elsevier B. V. All rights reserved.