 Hafnium had been predicted by Dmitri Mendeleev in 1869 and Henry Moseley measured in 1914 the effective nuclear charge by X @-@ ray spectroscopy to be 72 , placing it between the already known elements lutetium and tantalum . Dirk Coster and Georg von Hevesy were the first to search for the new element in zirconium ores . Hafnium was discovered by the two in 1923 in Copenhagen , Denmark , validating the original 1869 prediction of Mendeleev . There has been some controversy surrounding the discovery of hafnium and the extent to which Coster and Hevesy were guided by Bohr 's prediction that hafnium would be a transition metal rather than a rare earth element . While titanium and zirconium , as relatively abundant elements , were discovered in the late 18th century , it took until 1923 for hafnium to be identified . This was only partly due to hafnium 's relative scarcity . The chemical similarity between zirconium and hafnium made a separation difficult and , without knowing what to look for , hafnium was left undiscovered , although all samples of zirconium , and all of its compounds , used by chemists for over two centuries contained significant amounts of hafnium . 
