The vibrational frequencies of several silanes H3SiX (X=BH2, AlH2, PH2and SH) are determined. The infrared and Raman spectra are plotted. Several scale procedures were use to improve the theoretical spectra. The geometric parameters in theplanar, staggeredandeclipsedstructures of these species are fully optimized and compared with ab initio calculations. Basis set effects on the calculated structures are discussed. A few thermodynamic parameters, net atomic charges, dipole moment and energy are also computed.