hafniumn.
/ˈhafnɪəm/, U.S. /ˈhæfniəm/ Chemistry.
A metallic element with a silver lustre usually found associated with zirconium, which it closely resembles chemically, and used in nuclear reactor control rods. Symbol Hf; atomic number 72. Earlier called celtium n.
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celtium1911
hafnium1923
1923 Coster & Hevesy in Nature 20 Jan. 79/2 For the new element we propose the name Hafnium (Hafniae = Copenhagen).
1955 Sci. Amer. Oct. 35 In its ores zirconium is invariably accompanied by hafnium, which absorbs neutrons all too readily.
1957 Bull. Amer. Physical Soc. 2 269/1 Hafnium's thermionic efficiency in terms of grams evaporated per unit electron emission is slightly greater than that of Th metal.
1967 W. H. Kohl Handbk. Materials & Techniques for Vacuum Devices xii. 329/2 The high neutron absorption of hafnium, its excellent corrosion resistance in high-temperature water, and its adequate strength at reactor operation temperatures make this metal suited as a control material.
This entry has not yet been fully updated (first published 1933; most recently modified version published online March 2022).
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n.1923