The molecular structure, conformation, vibrational spectra, and torsional potential of perchlorovinylsilane (PCV), Cl2C=CCl-SiCl3, have been studied by using gas-phase electron diffraction (GED) data at 100 degrees C and variable temperature Raman spectroscopy, together with ab initio molecular orbital calculations. The GED data were treated by using a dynamic theoretical model. This involves fitting a chosen two-term potential function to the experimental data, thereby obtaining values for both a 3-fold and a 6-fold potential constant (V-3 and V-6) in the series V(phi) = 1/2 Sigma(i)V(i)[1 - cos i(180 - phi)], where phi is the value of the torsional angle CCSiCl. According to the GED refinements, this molecule exists in the gas phase at 100 degrees C as a mixture of two minimum-energy conformers, syn (torsional angle phi(CCSiCl) = 0 degrees or 120 degrees) and anti (torsional angle phi(CCSiCl) = 180 degrees), where the anti form predominates, occupying approximately 80% of the gas composition. Relevant structural parameters are as follows(anti): Bond lengths(r(g)): r(Si-C) 1.863(13) Angstrom, r[(Si-Cl)] = 2.020(3) Angstrom (average value), r(C=C) 1.349(12) Angstrom. Bond angles (angle(alpha)): angle[CSiCl] = 111.1(15)degrees, angle CCSi = 124.0(12)degrees. Error limits are given as 2 sigma (sigma includes estimates of uncertainties in voltage/height measurements and correlation in the experimental data). The estimated experimental conformational energy difference obtained from GED is Delta E degrees(A-S) = -1.04(+/-0.58) kcal/mol, based on the refined value of the V-3 potential constant. From the variable temperature Raman study, two corresponding energy differences obtained from two separate pairs of doublets in the liquid phase are Delta E degrees(A-S) = -0.30(1) and Delta E degrees(A-S) = -0 43(5) kcal/mol. The ab initio value (HF/6-31G(d)) was Delta E degrees(A-S) = -1.43 kcal/mol. All results suggest that anti is the low-energy form. Full geometry optimizations were performed for seven pseudoconformers (including 120 degrees and 180 degrees forms), which were employed in the dynamic GED model, by using the a.b initio MO HF/6-31G(d) level of theory. Scaled HF zero-point vibrational energy corrections were estimated from frequency calculations. The theoretical results are compared with experimental observations.