Electronic Absorption Spectra of Square-Planar d8 Complexes in Different Crystal Environments

Abstract

Polarized crystal spectra of K₂PdCl₄ and K₂PtCl₄ have been measured at room temperature and interpreted by means of a vibronic intensity‐borrowing mechanism. Single‐crystal spectra of Magnus's green salt, Pt(NH₃)₄PtCl₄, and its methylamine analog have also been measured, together with the powder spectra of a wide range of related salts. The visible absorptions are assigned to d—d transitions within axially perturbed anions, while a new infrared band in Magnus's green salt is identified with an intermolecular electron‐transfer transition.