INFRARED SPECTRA OF MNO4- ION IN ALKALI HALIDE MATRICES

The 300-1000-cm-1 spectra of KMnO4 embedded in KCl, RbCl, KBr, and RbBr peUets have been recorded at about 40°C and at liquid-nitrogen temperature in the concentration range 1/100 to 1/6000 molar ratios. In the chloride pellets, the fundamental modes of permanganate show many components which obey the selection rules of the unit cell of crystalline salt. Very sharp single bands of isolated tetrahedral MnO4- ion occur in the spectra of bromide pellets, superimposed on the bands of crystalline permanganate. The formation of solid substitutional solutions of MnO4- in alkali halide pellets is discussed in relation to size and symmetry of the occupied site of the host lattice.