Titanium, Zirconium, and Hafnium

Titanium, zirconium, and hafnium belong to the transition Group IV B elements of the periodic table. A characteristic feature of these transition elements is the ease with which they form stable complex ions. Features that contribute to this ability are favorably high charge-to-radius ratios and the availability of unfilled d orbitals. The facility in forming metallic bonds is demonstrated by the existence of a wide variety of alloys among different transition metals. Another feature of these metals is characterized by their high densities, high melting points, and low vapor pressures. Within this group, these properties tend to increase with increasing atomic weight. This chapter discusses the chemical and physical properties followed by the toxicity of each chemical and compound in three sections: Section A provides details on titanium, Section B on zirconium, and Section C on hafnium. Tables present the atomic number, atomic weight, and natural isotopes of titanium, zirconium, and hafnium. Keywords: Titanium; Zirconium; Hafnium; Physical and chemical properties; Production; Use; Toxic effects; Exposure assessment; Occurrence; Alloys; By products; Lung function; Standards; Guidelines; Regulations; Superalloys; Titanium compounds; Zirconium compounds; hafnium compounds