ABSTRACT
Geochemical characteristics of the metals of group 5, vanadium (V), niobium (Nb), and tantalum (Ta), are variable, although all elements exhibit mainly lithophilic tendencies. Vanadium is widely distributed in terrestrial environments where it forms both cationic and anionic compounds. Two elements, Nb and Ta, have very similar atomic radius and resemble each other in geochemical properties (Table 10.1). Both metals are rather rare in the biosphere (Table 10.2), are highly associated with Fe, Ti, Mn, and Zr, and are likely to be concentrated in polymetallic concretions in the ocean bottom. All metals of this group reveal an af nity for oxygen bonds.
