Vapor phase infrared spectrum and coriolis coupling constants of pentacarbonyl(thiocarbonyl)chromium(0)

Several band contours have been successfully resolved in the high-resolution IR spectrum of pentacarbonyl(thiocarbonyl)chromium(0) vapor at ~312 K. However, PQR separations are only clearly discernible for the three v(CO) fundamentals (v₁,v₂ and v₁₆). The good agreement between the observed and calculated PR separations of the two a₁v(CO) modes (v₁ and v₂) verifies the C_4v prolate symmetrical top geometry of the molecule. From band shape analyses, the Coriolis coupling constants of the ev(CO) mode (v₁₆) and the e δ (CrCO) mode (v₁₇) are estimated to be —0.45 ± 0.05 and —0.80 ± 0.15, respectively.