Motions that exchange symmetry non-equivalent atoms within a molecule, referred to as fluxional processes or non-dissociative exchange mechanisms, are documented for many chemical species. Two very well-known examples are the axial/equatorial hydrogen exchange in cyclohexane and the Berry pseudorotation that exchanges the axial and equatorial atoms in trigonal bipyramidal compounds. An interesting aspect of inorganic molecular structure of such intramolecular reactions is the characterization of the rearrangements of fluxional molecules.