The Pt compound below shows an infrared band at 822 cm-1 that has been attributed to the O-O stretching mode. This is the mode where the O atoms move away from each other and the Pt-O stretching is not significant. If you approximate the O-O unit as a harmonic oscillator, where would you expect the 18-O compound to absorb?
keywords: O-18, O-16, O16, O18, 16O, 18O, oxygen, oxygen-16, oxygen-18
The solution shows how to predict the frequency of an infrared absorption by looking at isotope effects.