Solid pure ruthenium phthalocyanine, obtained from its adduct [PcRu(DMSO)(2)].2DMSO, is an amorphous material, and its structure has been examined by the large-angle X-ray scattering (LAXS) technique. Experimental data are best fitted by assuming that ruthenium phthalocyanine is dimeric, i.e. (PcRu)(2), with a short intradimer Ru-(II)-Ru(II) contact (2.40 Angstrom), six dimeric units, on average, closely approaching one another and stacked in a monodimensional array. (PcRu)(2) is paramagnetic with a room-temperature magnetic moment (2.54 )B), which is strongly temperature dependent in the range 300-6 K. Interpretation of the magnetic behavior leads to an electronic energy level diagram which locates the highest energy electrons for the dimer in the orbital sequence sigma(2) pi(4) delta(2) delta*(2) pi*(2). The electrical conductivity value sigma(RT), 1 x 10(-5) Omega(-1) cm(-1) is also considered in the light of the structural features of the complex. (PcRu)(2), stable to air as a solid material, easily interacts with dioxygen when in contact with tetrahydrofuran. Dioxygen activation and oxygen atom transfer are observed for ruthenium phthalocyanine in the oxidation of 1-octene by O-2 in tetrahydrofuran, in the presence of (C6H5CN)(2)PdCl2 as the olefin activator, with selective formation of 2-octanone. Catalytic experiments were carried out at room temperature and at a p(O-2) of 50 atm. The optimized conditions for oxidation involve a Fe:Pd:olefin molar ratio of about 1:1.7:40.