Single Crystal EPR and Optical Studies of Cu(II) Doped Zinc Ammonium Phosphate Hexahydrate: A Case of Rhombic Distortion

Abstract

Single crystal EPR and optical studies of Cu(II) doped ZnNH4PO4 · 6H2O (Zinc struvite) have been carried out at room and liquid nitrogen temperatures. The g and A tensors indicate that the impurity has entered the lattice substitutionally. Even though the coordination polyhedron around the host Zn(II) is a compressed octahedron of oxygen atoms of water, the Cu(II) ion has an elongated octahedron corresponding to dx2-y2 ground state. The optical spectrum shows four bands at 1205, 1095, 833 and 805 nm, which confirms the octahedral coordination of Cu(II) with rhombic (C2V) distortion.