AbstractThe Raman (3500−10 cm−1) and infrared (3500−20 cm−1) spectra of CH3PF2BH3and CH3PF2BD3were recorded for the gaseous and solid states. Additionally, the Raman spectrum of the liquid was recorded and qualitative depolarization values were measured. All the fundamental modes except the two internal rotations were assigned utilizing band contours, depolarization values, isotopic shifts and group frequencies. A normal coordinate calculation was carried out utilizing a modified valence force field to calculate the frequencies and the potential energy distributions. The observation of five Raman lines in the spectrum of the solid, and the observation of the doubling of several of the intramolecular fundamentals, indicate that there are at least two molecules per primitive cell. These results are compared with similar quantities in some corresponding mo