Knowledge Bank

“The infrared spectra of gaseous $CFa$ $CF2Br$ and $CF2H-CF2Br$ and the Raman spectra of the liquids have been obtained at room temperature. All but two of the fundamental vibrational frequencies of $CF2$ $CF2Br$ have been assigned. Since $CF2H-CF2Br$ exhibits rotational isomerism, measurements of its infrared band intensities were made at different temperatures up to $185\circ C$, and the infrared spectra of the liquid, at $-60\circ C$, and solid, at $-170\circ C$, were recorded. Also, the Raman spectrum of the liquid was observed at $-85\circ C$. An attempt is being made to identify the fundamentals of the individual isomers. Preliminary measurements give 310 cal $deg-1$ $mole-1$ for $\Delta H00$.”