Symbol

Hf

Atomic Number

72

Atomic Mass

178.49

Family

Group 4 (Ivb) Transition Metal Pronunciation

HAF-nee-um

Overview

Hafnium is an element that chemists knew existed, but could not find. They knew it must exist because of an empty space in the periodic table. The periodic table is a chart that shows how chemical elements are related to each other.

By the twentieth century, nearly all the spaces in the periodic table had been filled. One of the empty spaces was element 72. A number of chemists searched for the element. Some even claimed they had found it. But these claims were not confirmed. In fact, it was not until 1923 that element number 72 was finally discovered.

Hafnium is a shiny, silvery-white metal. It is always found with another chemical element, zirconium. The two elements are very much alike. In fact, their similarity is the reason that it took so long to find hafnium...