Zirconium phosphonates

This contribution presents a survey of the various aspects of the chemistry of Zr phosphonates, throughout 30 years of activity of the Laboratory of Inorganic Chemistry of Perugia on this topic. These inorganic–organic compounds are characterized by a very low solubility and chemical robustness, and their structure and reactivity can be easily modulated by the right choice of the organophosphonic group. Since the preparation of the first zirconium benzenephosphonate in 1978, a large number of different compounds of this class, with different structure, dimensionality (from 1D linear chain, 2D layered to 3D open-framework) and properties, has been obtained. The use of di- or polyphosphonate building blocks further enriched this variety. This chapter will try to enlighten similarities between them, on the basis of their structure and reactivity. Following this line the chapter is divided into three main sections: alfa-Zr phosphonates; gamma-Zr phosphonates; new compounds mainly based on aminophosphonate building blocks.