Freshly distilled, Dry Ice-cooled VCl4 (40 g) is added to 130 g of similarly cooled anhydrous HF contained in a reactor. A copper reflux condenser charged with a cooling mixture is then attached to the vessel, and the reaction mixture is allowed to warm slowly to 0°C. The mixture is then boiled for several hours until no further HCl evolves. The reflux condenser is then replaced by a descending condenser, and the HF is distilled off. The VF4 remaining in the reactor is freed of any traces of HF by passing a dry stream of nitrogen at 50°C. The yield is 97%, based on VCl4. The product may be stored in sealed iron or copper containers.
