ESR of Cu2+ (H2O)6. I. The oxygen-17 superhyperfine tensors in 63Cu2+ doped zinc Tutton's salt at 20 °K

Abstract

The X‐band ESR spectrum of 63Cu2+dopedzinc Tutton's salt enriched to 16 at.% in oxygen‐17 isotope was studied in a completely deuterated single crystal at 20°K. Satellites from both singly and doubly labelled molecules were observed and the oxygen‐17 superhyperfine tensors were found to differ for the two trans pairs of equatorial oxygens. The two tensors are −21.0, −11.9, and −10.9×104 cm−1 and −16.1, −9.9, and −8.8×104 cm−1, where the largest principal value in each case is directed along the copper‐oxygen bond and the tensors are associated, respectively, with the shorter and longer of the equatorial copper‐oxygen bonds. The tensors, after correction for a distant dipolar contribution from the metal, were shown to imply a value of 1/6 for the ratio 2s 0/2p 0 in the molecular orbital containing the unpaired electron. This result is discussed in terms of the known geometry of the Cu2+(H2O)6 complex in Tutton's salts.