Prepd by passing gaseous boron trichloride through flow discharge between mercury or copper electrodes: Urry et al., J. Am. Chem. Soc. 76, 5293 (1954); Wartik et al., Inorg. Synth. 10, 118 (1967); by passing boron trichloride vapor over boron monoxide at 200°: McCloskey et al., J. Am. Chem. Soc. 83, 4750 (1961). Infrared and Raman spectra: Linevsky et al., J. Am. Chem. Soc. 75, 3287 (1953). Review of boron halides: Massey, Adv. Inorg. Chem. Radiochem. 10, 1-152 (1967).