Stability and Reversible Oxidation of Sub-Nanometric Cu₅ Metal Clusters: Integrated Experimental Study and Theoretical Modeling**

David Buceta, Shahana Huseyinova, Miguel Cuerva, Héctor Lozano, Lisandro J. Giovanetti, José M. Ramallo-López, Patricia López-Caballero, Alexandre Zanchet, Alexander O. Mitrushchenkov, Andreas W. Hauser, Giampaolo Barone, Cristián Huck-Iriart, Carlos Escudero, Juan Carlos Hernández-Garrido, José Juan Calvino, Miguel López-Haro, María Pilar de Lara-Castells^*, Félix G. Requejo^*, M. Arturo López-Quintela^*