Amorphous potassium pentacyanonitrosylruthenate (II) was synthesized and characterized by UV, IR, X-ray diffraction and thermogravimetric analysis. Electron Spin Resonance spectroscopy reveals the presence of paramagnetic ruthenate (I) complexes and NO2 radicals in the X-irradiated diamagnetic salt. Spin-hamiltonian parameters of the [Ru(CN)5NO]3- complex (g<FONT FACE="Symbol">^</FONT > or = 2.0064, A<FONT FACE="Symbol">^</FONT> (14N) = 60.7 MHz, g|| = 1.999, A|| (14N) = 77.3 MHz ) support an electron capture in a pi* molecular orbital of the nitrosyl group mixed with d xz and d yz ruthenium orbitals as recently predicted by theoretical calculations. Silver ions, present as impurities, are reduced to Ag(0) by X-irradiation and coordinate to four magnetically equivalent nitrogens in a distorted site, giving rise to a well resolved anisotropic ESR powder spectrum.
pentacyanonitrosylruthenate; ESR; radiation damage
