EPR of Fe3+ in CsCl and NH4Cl

Abstract EPR of Fe 3+ in CsCl and NH 4 Cl was studied between 20 and 293 K. In CsCl two tetragonal centers with zero field splittings in the approximate intensity ratio of 2 were observed at room temperature. Application of the superposition model allowed tentative models for their coordinations to be derived from those of divalent transition metal ions by exchange of an axial water ligand against OH − and Cl − , respectively. In NH 4 Cl one tetragonal and four monoclinic centers are observed at low temperatures only. These low symmetries and dynamical effects most likely result from hydrogen bonding due to the smaller lattice constant compared to CsCl analogous to the results for Cu 2+ in NH 4 Cl.