The chemistry of rare earth metals, compounds, and corrosion inhibitors

The chemistry of rare earths is fundamental to an understanding of the role of rare earths as corrosion inhibitors and to the preparation of effective rare earth-containing inhibitors. This chapter defines rare earth elements and their place in the Periodic Table, including electronic configurations, oxidation states and the lanthanoid contraction, their discovery, location and abundance, and their uses other than as corrosion inhibitors. A major section is devoted to the general chemistry of rare earths elements, oxides, hydroxides, salts and coordination compounds, and includes a discussion of their separation together with a brief account of their spectra and magnetic properties. A further section deals with rare earth carboxylate complexes as these are promising inhibitors. Their synthesis and structures are described together with attempts at modelling their behaviour on iron (steel) surfaces. Ongoing problems are also considered.