INFRARED SPECTRA OF BISMUTH TRIFLUORIDE AND CHLORODIBORANE. ATTEMPTED PREPARATION OF BISMUTH HYDRIDE FOR INFRARED STUDY

Bismuth trifluoride was prepared as a precipitate from the addition of potassium trifluoride to a solution of bismuth nitrate dissolved in nitric acid. Infrared spectra of Nujol mulls and cesium bromide pellets containing bismuth trifluoride gave only two of the four absorption bands expected. One band was at 523 and the other a broad band at 258 wave numbers. The production of sufficient quantities of bismuth hydride (Bismuthine) for infrared study was attempted by two methods. The method used by Paneth in 1919 involved preparing a magnesium-bismuth alloy. The alloy was treated with acid; bismuth hydride was reported as one of the gaseous products evolved. The second method of production was proposed by Schaeffer in 1954. Lithium borohydride in aqueous solution was added to a solution of bismuth trichloride dissolved in hydrochloric acid. The lithium borohydride used in the attempted production of bismuth hydride by the Schaeffer method was obtained commercially and contained chlorine as an impurity. The gas from the hydrolysis reaction with sulfuric acid gave the diborane spectra. The infrared spectrum of the gas evolved from the hydrolysis of the commercial lithium borohydride with hydrochloric acid, water and sodium hydroxide is thought to be that of chlorodiborane.