Fluoro and mixed-ligand fluoro complexes of copper(II). A new synthesis of KCuF₃, and synthesis and physico-chemical studies of new mixed-ligand fluorocuprates(II), A[CuF(SO₄)].nH₂O (A = Na, n=2; A=K or NH₄, n=3)

Abstract

White crystalline KCuF₃ has been synthesized from the reaction of Cu(OH)₂ with KHF₂ and a small amount of 40% HF at pH ≤ 4, while the synthesis of blue fluoro(sulphato)cuprates(II), Na[CuF(SO₄)]. 2H₂O, K[CuF(SO₄)].3H₂O and NH₄[CuF (SO₄)].3H₂O, has been accomplished by reacting Cu(OH)₂ with AF and A₂SO₄ (A = Na, K or NH₄), in the ratio of 1:1:1, in the presence of a small amount of 40% HF. Alternative synthesis of the latter involving reactions among Cu(OH)₂, F^-, and SCN^-, and H₂O₂ or SO₂(g) and H₂O₂ gave CuSCN and Cu¹¹[Cu¹SO₃]₂. 2H₂O, respectively, instead of the desired product. The compounds have been characterized by elemental analyses, chemical determination of the oxidation state of copper, magnetic susceptibility and ESR measurements, IR, laser Raman (LR), and electronic spectroscopic studies. The complex [CuF(SO₄)]^- species has a distorted octahedral polymeric structure containing both F^- and SO₄^2- as bridging ligands.