Knowledge Bank

Recent studies in this laboratory have suggested that the relatively low-lying allowed transitions in planar $d8$ complexes may in some cases involve a $d\to p$ type ``metallic'' transition. In order to investigate this possibility further, the polarized single-crystal reflection spectra of the square-planar tetraammine complexes of palladium(II) and platinum(II) have been determined. These spectra will be reported and discussed in light of previous results obtained here and elsewhere, and in terms of existing theory for planar complexes.