An alternative explanation for the anomalous infrared spectra of HCrO2 and DCrO2

Abstract

Fermi resonance between a broad v (OD) fundamental and a sharp 28(ODO) overtone is postulated to be the cause of the verydifferent appearance of the v(0H) and v(OD) i.r. absorption bands of HCrO, and DCrO,.

Associated XH Frequencies, the Hydrogen Bond

“…In particular, some compounds such as the phosphinic and arsinic acids show no relationship between the ABC bands and the positions of the OH deformations [291]. A similar mechanism has been proposed to explain the otherwise anomolous spectra of HCr0 2 and DCr0 2 in which the OD stretching bands appear to occur at higher frequencies than the OH [261]. This is interpreted by Clayton and Sheppard [291] in terms of a different type of Fermi resonance interaction previously reported by Evans as the source of transmission windows in spectra [156].…”

“…The vibration of the XH bond involves an anharmonic potential energy well, and the fact that the zero-point energy of hydrogen is greater than that of deuterium necessarily implies that the anharmonicity will be more strongly felt by the hydrogen atom. An exception to this is the compound Cr0 2 H which is thought to have a symmetric hydrogen bond but which has an OH/OD ratio of less than 1 [20,261]. In some very short but unsymmetrical hydrogen bonds the ratio can actually fall to 1.0 and no shifts are seen on deuteration although there is some reduction in the band intensity [256,260].…”

Development of Alkaline Oxidative Dissolution Methods for Chromium (III) Compounds Present in Hanford Site Tank Sludges

“…Based on the spectra, it is difficult to confhm the presence or absence of CrOOH phases in II-IX. The CrOOH phases are characterized by a weak and broad band at -1600 cm-l [Snyder and Ibers 1962;Claydon et al 1975] that would be obscured by the overlying bands from Cr(lIl) hy~oxide. (Table 2.2).…”