The structure and activation of the phosgene molecule. Part II.—The Raman spectrum of phosgene

Abstract

The vessel in which the phosgene was contained for illumination was a glass tube 3 cm. diameter and 10 cm. long, closed at one end and ending at the other in a “tail” bent at right angles. The tail had a bulb of about 25 c. c. capacity to allow for subsequent expansion of the liquid after filling at low temperature, and it was coated with black wax to prevent reflection from this end of the vessel. This Raman tube was filled in the following way. A stream of phosgene from a bomb (supplied by Messrs. Siegfried, of Zofingen) was led through a glass coil cooled in a freezing mixture of ice and salt. The condensed phosgene was received in a bulb of about 120 c. c. capacity cooled in ether and carbon dioxide ice. The bulb was joined to the Raman tube and a side tube was provided for evacuation. When a sufficient quantity of liquid had been collected, the receiving bulb was sealed off from the condenser coil, the two bulbs were evacuated through calcium chloride tubes by means of a water-pump and the side tube was sealed off. The Raman tube was then cooled in alcohol and carbon dioxide ice and the receiving bulb allowed to warm slowly, so that the phosgene distilled over quietly without ebullition. When the requisite amount was present, the tube was sealed off. The liquid produced in the initial condensation was somewhat cloudy but on redistillation into the Raman tube it was obtained perfectly clear.