The molecular structures of Cl 3 V = NCl and Cl 3 V = O were determined by gas-phase electron diffraction. For both molecules the r α 0 -structure was converted to restructure. In the case of Cl 3 V=O the necessary corrections were taken from the literature while for Cl 3 V=NCl an approximate force field was evaluated from the infrared spectra of the solid compound for calculating these corrections. The following rα 0 parameters were derived for Cl 3 V = NCl: V = N = 1,651 (6), N-Cl = 1,597 (8), V - Cl = 2,138 (2), ⦓ ClVCl = 113,4° (0,3) and ⦓ VNCl = 169,7° (4,2). The most interesting result of this investigation is the structure of the V = N -Cl group which is almost linear and has a very short N -CI bond distance. Concerning the VNCl group the gas-phase results agree very well with the crystal structure. For vanadyl chloride the following rα 0 -values were obtained: V = 0 = 1,571 (4), V - Cl = 2,137 (1) and ⦓ ClVCl = 111,0° (0,1°). The error limits given in thousandth parts of an Angstrom or degrees are the threefold standard deviations of the least squares analysis.