Copenhagen, Denmark/180
Previous | Home | Next"Hafnium salts of various purities, from the 1920s." A major reason why hafnium is so similar to zirconium in its physical and chemical properties is the similar atomic radii of the two elements. Hafnium is smaller than anticipated because of the lanthanide contraction, a phenomenon whereby the atomic radii of the lanthanides contract as one proceeds from lanthanum (atomic number 57) through lutetium (atomic number 71). The phenomenon of the lanthanide contraction also is responsible for the similar behavior of niobium and tantalum {LINK: to Berlin museum to niobium}.
