Köksal F.Köseoglu R.Başaran E.2019-08-012019-08-0120030932-0784https://dx.doi.org/10.1515/zna-2003-5-607https://hdl.handle.net/11480/1351Rhyolite from the "Yellow Stone of Nevşehir" and ?-irradiated trona from the Ankara Mine have been investigated by electron paramagnetic resonance at ambient temperature and at 113 K. Rhyolite was examined by X-ray powder diffraction and found to consist mainly of SO2. Before ?-irradiation, the existing paramagnetic species in rhyolite were identified as ?O4 2-, CH2OH, CO3 -, ?O2 -, CO3 3-, and CO2 - free radicals and Fe3+ at ambient temperature. At 113 K ?O2 -, CO3 3-, and CO2 - radicals and Fe3+ were observed. The ?-irradiation produced neither new species nor detectable effects on these free radicals. The disappearance of some of the radicals at 113 K is attributed to the freezing of their motions. Before ?-irradiation, the trona mineral shows only Mn2+ lines, but after ?-irradiation it indicated the inducement of CO3 3- and CO2 - radicals at ambient temperature, 113 K, in addition to the Mn2+ lines. The g and a values of the species were determined.eninfo:eu-repo/semantics/openAccessElectron Paramagnetic ResonanceFree RadicalsRhyoliteSilicateTrona?-IrradiationArticle584544829329810.1515/zna-2003-5-6072-s2.0-8144223754Q3WOS:000184274600006Q3