COMPARATIVE-STUDY OF THE STRUCTURAL, ELECTRONIC, AND MAGNETIC-PROPERTIES OF THE LAYERED TERNARY VANADIUM-OXIDES CAV4O9, CS2V4O9, AND [H2N(CH2)(4)NH2]V4O9

We report the preparation, single-crystal X-ray structure determinatio n, and magnetic susceptibility measurements of a new ternary vanadium oxide, [H2N(CH2)(4)NH2]V4O9. This compound has isolated V4O92- layers made up of edge-sharing VO5 square pyramids. The V4O92- layers of [H2N (CH2)(4)NH2]V4O9([H2N(CH2)(4)NH2] = piperidinium) differ from those of two other ternary vanadium oxides, CaV4O9 and A(2)V(4)O(9) (A = Rb, C s), in the way the VO5 square pyramids are shared, and the magnetic su sceptibilities of the three oxides are widely different in their maxim um susceptibility values and the temperatures where these values occur . To explain these observations, the electronic structures of the thre e oxides were analyzed based on molecular orbital calculations.