title: Changeover during in situ compositional modulation of hexacyanoferrate (Prussian Blue) material.
abstract: This paper describes the importance of (H2O)6 clusters in controlling the properties of hexacyanoferrate (Prussian Blue) materials. A careful in situ study of compositional changes by using electrogravimetric techniques (in ac and dc modes) in hexacyanoferrates containing K+ alkali metals reveals the existence of a changeover in the properties of these films in a narrow potential range. Control of the compositional variation of the changeover is dependent on the K+ stoichiometric number in the compound structure. However, a specific K+ occupation in the compound structure activates the occupation of the (H2O)6 cluster by H3O+ and/or H+, causing the changeover in the properties of hexacyanoferrate film. Thus, the information thus obtained is very useful for understanding the mechanisms involved in the electrochemical reversible switch between ferrimagnetism/paramagnetism, "semiconductor/metal" and electroluminescence/nonelectroluminescence properties of molecular cyanide materials.
authors.affiliation: Instituto de Química, Departamento de Físico-Química, Universidade Estadual Paulista, 14801-907 Araraquara, São Paulo, Brazil.
authors.forename: Paulo Roberto
authors.initials: PR
authors.lastname: Bueno
authors.forename: David
authors.initials: D
authors.lastname: Giménez-Romero
authors.forename: Claude
authors.initials: C
authors.lastname: Gabrielli
authors.forename: José Juan
authors.initials: JJ
authors.lastname: García-Jareño
authors.forename: Hubert
authors.initials: H
authors.lastname: Perrot
authors.forename: Francisco
authors.initials: F
authors.lastname: Vicente