Paramagnetic resonance absorption in approximately a hundred salts in the powder form, containing atoms of the iron and rare earth groups and organic as well as inorganic radicals, has been investigated. The frequencies employed range from 9000 to 50,000 Mc/sec. Exchange interaction which affects markedly the line widths and shape was found to be of wide occurrence even in ions separated by large organic radicals. The results indicate that paramagnetic resonance is a promising new method of investigating the orbital properties of these organic radicals. Evidence has been found in copper acetate for the simultaneous transition of electrons in neighboring ions with the absorption of a single quantum.