Low-Temperature Magnetic Characteristics of Tetrahedral CoCl4 2−. I. g-Tensor Orientation in Doped [(C2H5)4N]2ZnCl4

Electron paramagnetic resonance measurements were made on single crystals of cobalt-doped tetraethylammonium tetrachlorozincate (II) at 4.2°K. The results show that the CoCl4 2− tetrahedra are oriented in several magnetically nonequivalent directions in the host lattice, which is isostructural with the analogous cobalt compound, tetraethylammonium tetrachlorocobaltate (II). Each tetrahedron can be characterized by an effective spin S′= 12 and by the principal g values gx ′=5.44, gy ′=4.84, and gz ′=2.34. Although the individual CoCl4 2− anions exhibit only rhombic symmetry, these ions are so oriented at 4.2°K as to maintain the tetragonal axis exhibited by the crystal at room temperature.