Which Of The Following Lacks A Vibrational Absorption Spectrum?

Homonuclear diatomic molecules such as H2, O2, N2, and others, possess only stretching motions or vibrations and lack any bending motions or vibrations. In these molecules, the dipole moment remains constant throughout the vibration. Consequently, they do not produce vibrational spectra and are classified as “infrared-inactive.” This means that when subjected to infrared radiation, they do not exhibit characteristic absorption peaks in the resulting spectrum, providing a distinctive feature for their identification.

An illustrative instance of a vibrational spectra can be observed when examining the change in mass of an aqua ligand that transitions to manganese (Mn) and subsequently deprotonates to form hydroxide. Vibrational spectroscopy plays a crucial role in detecting this phenomenon. These vibrational spectra manifestations primarily occur within the low-frequency region of the vibrational spectrum, typically ranging from approximately 200 to 600 cm−1. Within this range, one can observe the vibrations associated with the bonds between the metal and ligands within metal clusters, providing valuable insights into their structural characteristics.