Crystal field environments provided by the sulphate ligand

Abstract

The d–d absorption bands of first-row transition-metal ions are reported in the three sulphate media: K₂SO₄–ZnSO₄ glass, NaHSO₄–KHSO₄ glass, and concentrated sulphuric acid. The spectroscopic parameters are in accordance with the formation of chelated sulphato-complexes in the K₂SO₄–ZnSO₄ glasses, but in the NaHSO₄–KHSO₄ glass and in sulphuric acid the sulphate ions act as unidentate ligands.