Vibrational Spectra of Vanadium Pentafluoride

The infrared spectrum of VF5 vapor has been studied from 140 to 4000 cm−1. The Raman spectrum has been obtained for the vapor and for the liquid at various temperatures. The spectra indicate a D3h symmetry for the molecule. Fundamental vibrational frequencies observed are: a1′, 719 and 608; a2″, 784 and 331; e′, 810, 282, and (∼200); e″, 350; all in cm−1. Approximate bond-stretching force constants for a modified Urey—Bradley potential function are: Kr=5.51 Mdyn/Å, Kd(axial)=3.94 Mdyn/Å. The Raman spectra show that monomeric molecules are in low concentration in the room-temperature liquid but constitute the main component in the liquid at temperatures above 100°C.