in neat (no solvent) heating (evacuated quartz cell, 325°C, 2 h); according to Wehrli, M., Miescher, E., Helv. Phys. Acta 7, 298 (1934) and to Barrow, R. F.,et al., Trans. Faraday Soc. 51, 1657 (1955);

in gaseous matrix In vaporization (Nd:YAG -532 nm), Ne backing gas, 0.05percent Br2, total static pressure 1-2 atm.;