Normal Coordinate Treatments and Calculated Thermodynamic Properties of Phosphoryl Chloride, Thiophosphoryl Chloride, and Phosphoryl Fluoride

Abstract

The infrared and Raman spectra for phosphoryl chloride, thiophosphoryl chloride, and phosphoryl fluoride were collected and examined for the most probable values for the wave numbers, intensities, and depolarization factors. The data are as follows: The Raman displacements Δσ in cm—1, the relative intensities I, and the depolarization factors ρ are for POCL3: Δσ(1)ρ = 192.85 (8) 0.83, 267.39 (6) 0.64, 337.44 (7) 0.81, 486.24 (10) 0.05, 581.2 (3) 6/7, and 1289.9 (5) 0.04; for PSCl3: 172 (5) 6/7, 247 (7) 6/7, 247 (calculated) 430 (10) 0.1, 538 (1) 6/7, and 753 (1) P; and for POF3: 337 (w) 6/7, 476 (m) 6/7, 483 (from infrared) P, 875 (s) 0.05, 982 (vw) 6/7, and 1395 (m) 0.1. As for the infrared spectral data, those of G. Cilento et al., were used for PSCl3, and those of Gutowsky and Liehr were used for POF3. No published infrared spectral data were found for POCl3. Also normal coordinate treatments were conducted for POCl3, PSCl3, POF3, and PSF3 on the basis of a model having C3v symmetry. The normal coordinate treatments gave the listed wave numbers as fundamentals and lend support for the 247 cm—1 band for PSCl3 and 483 cm—1 band (observed in the infrared and assigned as fundamental by Gutowsky and Liehr) for POF3 as the missing Raman bands. Moreover, the F matrix elements obtained for these molecules were determined in such a manner that those potential constants for the PCl3 group had nearly the same values in both POCl3 and PSCl3, those for the PF3 group had nearly the same values in both POF3 and PSF3, the one for the PO group had nearly the same value in both POCl3 and POF3, and the one for the PS group had nearly the same value in both PSF3 and PSCl3. The potential constants determined had the following values in md/A: For POCl3, fPO=9.890, fPCl=2.466, fPClPCl=0.399, for PSCl3, fPS=0.030, fPCl=2.466, fPClPCl=0.399; for POF3, fPO=9.890, fPF=5.633, fPFPF=0.483, and for PSF3, fPS=2.9694, fPF=5.333, fPFPF=0.183. Finally, the values of the thermodynamic properties for these substances were computed for the ideal gaseous state using the rigid rotor harmonic oscillator approximation at 1 atm from 200° to 1000°K.