Metal clusters that may serve as models for both homogeneous and heterogeneous catalysis of reactions of carbon monoxide and hydrogen are under investigation in the laboratory of John S. Bradley at Exxon Research & Engineering Co. The characteristic feature of the metal clusters Bradley studies is the presence of a bare carbon atom which, apparently, can form a carbon-carbon bond with carbon monoxide. This reaction begins the buildup of an organic molecule fragment attached to the metal cluster. So far, Bradley's group can make small oxygen-containing organic molecules, such as methyl acetate, in reactions directed by these metal clusters. They can remove the product from the cluster and regenerate the cluster, thus forming a reaction cycle. Regenerating the cluster in its active form requires addition of an oxidizing agent, however, so the cycle cannot be thought of as catalytic. Nevertheless, Bradley says, many of the steps in the cycle, particularly those involving reaction of the ...