Complex halides of the transition metals. Part III. Electronic spectra and ligand field parameters of octahedral and tetrahedral halogeno-complexes of manganese(II)
The electronic spectra of a number of compounds of manganese(II) in which the metal is surrounded by an octahedral arrangement of halogen atoms have been analysed, and values for the Racah parameters, B and C, and the ligand-field parameters, Δ, calculated. The compounds include MnX2(X = F, Cl, Br, I), (MeNH3)2MnCl4, α-Cs2MnCl4, K4MnCl6, KMnCl3, Me4NMnCl3, and Me4NMnBr3. The values obtained for Δ are 7500, 5200–6200, 5600–5800, and 5500 cm.–1 for the fluorine, chlorine, bromine, and iodine compounds respectively, and they are compared with those for the tetrahedral arrangement of the ligands about the metal ion. X-Ray diffraction data have shown that (MeNH3)2MnCl4 has the K2NiF4 structure with unit cell dimensions a 7·20, c 19·37 Å, and that the structures of Me4NMnCl3 and Me4NMnBr3, with unit cell dimensions a 9·13, c 6·49, and a 9·44′c 6·76 Å, respectively, are related to that of CsNiCl3.