Electron paramagnetic resonance study of Cr3+ ions in (NH4)1-xMxAl(SO4)2 · 12H2O (M = K, Na) mixed alums

Abstract The EPR of Cr 3+ ion in mixed alums ( NH 4 ) 1- x M x AI ( SO 4 ) 2 · 12 H 2 O ( M = K , Na ) have been studied at room temperature. The value of “ g ” is found to be essentially constant. From the variation of the magnitude of D for different x it is found that K + and Na + have opposite effect on the distortion of M 3+ (H 2 O) 6 octahedron. The spin-orbit coupling constant is found to be reduced from its free ion value for Cr 3+ ion and is attributed to the bonding effects in the crystal.