11B NMR in the layered diborides OsB2 and RuB2

B-11 nuclear magnetic resonance (NMR) measurements have been performed on B-11 enriched OsB2 and RuB2 polycrystalline powder samples in an external field of 4.7 T and in the temperature range, 4.2 K < T < 300 K. The spectra for both samples show similar quadrupole powder patterns that are typical for a nonaxial symmetry. The Knight shifts K in both samples are very small and constant in temperature. The nuclear spin-lattice relaxation rate T-1(-1) follows a Korringa law in the whole temperature range investigated with T1T=600 and 680 sK for OsB2 and RuB2, respectively. The experimental results indicate that a p character dominates the conduction electron wave function at the B site with a negligibly small s character in both compounds.