Crystal Spectra of Metal Coordination Compounds. I. Tetrahedral Cobalt(II)

Abstract

A reflecting microscope has been used to measure the absorption spectra, in polarized light, of a number of cobalt(II) compounds in which the ligands are arranged tetrahedrally. These compounds are Cs₃CoCl₅, cobalt di‐p‐toluidine dichloride, cobalt dipyridine dibromide, and cobalt dipyridine diiodide. The two transitions, ⁴A₂→⁴T₁(F) in the near infrared and ⁴A₂→⁴T₁(P) in the visible, have been compared in the different compounds and the effect of symmetry discussed. It was also found that the crystal spectra of all but Cs₃CoCl₅ are modified by interaction between the complexes in the crystal so that the energy levels are not accurately described by the field of the ligands only.