Zirconium compounds chemical behaviors

Because of the effects of the lanthanide contraction, both the atomic radii of Zr and Hf (1.45 and 1.44 A, respectively) and the radii of the Zr4+ and Hf4+ ions (0.74 and 0.75 A, respectively) are virtually identical. This has the effect of making the chemical behavior of the two elements extremely similar, more so than for any other pair of congeneric elements. The chemistry of hafnium has been studied less than that of zirconium but only small differences, e.g., in solubilities and volatilities of compounds, are to be expected or found. 

Despite the close resemblance in chemical behavior of the metals and their compounds, thorium differs from titanium, zirconium and hafniiiTTi in one respect, and that makes the preparation of... 

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