Electron spin relaxation governed by Raman processes both for Cu2+ ions and carbonate radicals in KHCO3 crystals: EPR and electron spin echo studies

► Radiation defects were identified as CO3- and HOCO radical molecules. ► Localization of Cu2+ and the radicals in the crystal unit cell was determined. ► Raman processes govern the spin-lattice relaxation for Cu2+ and the radicals. ► The Debye temperature was calculated from elastic constants as 246 K.