The Infrared Spectra of CF4 and GeF4

Abstract

The infrared spectrum of CF₄ has been remeasured from 2–19μ and extended to about 33μ, and the infrared spectrum of GeF₄ has been observed from 2–38μ. Through the use of purer samples and more gas than in previous investigations, a large number of new overtones and combination bands were observed in CF₄, and several bands were eliminated as impurities. Identifications of these bands are given. The infrared‐inactive ν₂ was observed, probably because of interaction with ν₄, at 435 cm⁻¹ in agreement with the Raman line at 437 cm⁻¹. In GeF₄ the two active fundamentals ν₃ and ν₄ were observed at 800 cm⁻¹ and 260 cm⁻¹, respectively. Eight overtone and combination bands were discovered. From these the values of ν₁ and ν₂ were calculated to be 740 cm⁻¹ and 200 cm⁻¹, respectively. Compared with the fundamentals of GeCl₄ and GeBr₄, these frequencies seem reasonable. The most striking feature of the spectrum of GeF₄ is the scarcity of bands as compared with both CF₄ and SiF₄.