Isolated redox centers within microporous environments. 2. Vanadium-containing aluminophosphate molecular sieve five

Cobalt-containing aluminophosphate five (CoAPO-5) was synthesized and shown to contain tetrahedral Co{sup 2+} residing within framework atomic positions and also as extraframework cations. The isolated framework Co{sup 2+} atoms can be oxidized by O{sub 2} at 500{degree}C to Co{sup 3+} which is stabilized in tetrahedral coordination by the oxide lattice. The framework Co{sup 3+} is easily reduced to Co{sup 2+} by a variety of reducing agents.