General | States | Energies | Oxidation & Electrons |Appearance & Characteristics
Reactions | Other Forms |Radius | Conductivity | Abundance
Encyclopedia Britannica articles


Name Hafnium Symbol Hf
atomic number 72 Atomic weight 178.49
Density @ 293 K 13.2 g/cm3 Atomic volume 13.6 cm3/mol
Group Trans. Met. discovered 1923


state (s, l, g) s
melting point 2495.2 K boiling point 4723 K
Heat of fusion 24.060 kJ/mol Heat of vaporization 575.0 kJ/mol
Back to the top


1st ionization energy 680 kJ/mole electronegativity 1.3
2nd ionization energy 1440 kJ/mole electron affinity 0 kJ/mole
3rd ionization energy 2250 kJ/mole Specific heat 0.14 J/gK
heat atomization 619 kJ/mole atoms

Oxidation & Electrons

Shells 2,8,18,32,10,2 electron configuration [Xe] 4f14 5d2 6s2
minimum oxidation number 0 maximum oxidation number 4
min. common oxidation no. 0 max. common oxidation no. 4
Back to the top

Appearance & Characteristics

structure hcp: hexagonal close pkd color silvery
uses nuclear control rods toxicity
hardness mohs characteristics hard


reaction with air mild, w/ht, = HfO2 reaction with 6M HCl none
reaction with 6M HCl none reaction with 15M HNO3 passivated
reaction with 6M NaOH none
Back to the top

Other Forms

number of isotopes 6 hydride(s) HfH2
oxide(s) HfO2 chloride(s) HfCl3 HfCl4


ionic radius (2- ion) pm ionic radius (1- ion) pm
atomic radius 159 pm ionic radius (1+ ion) pm
ionic radius (2+ ion) pm ionic radius (3+ ion) pm
Back to the top


thermal conductivity 23.2 J/m-sec-deg electrical conductivity 28.49 1/mohm-cm
polarizability 16.2 A^3


source Zircon (silicate) rel. abund. solar system -0.812 log
abundance earth's crust 0.4 log cost, pure 120 $/100g
cost, bulk $/100g
Back to the top

World Wide Web presentation of Chemicool Periodic Table is © Copyright 1996-99 by David D. Hsu. Some data were provided by and used with the permission of JCE Software and is owned and copyright by the Division of Chemical Education, Inc. Additional data were provided by Perkin-Elmer through Peter Lykos of IIT. The information may not be redistributed without the permission of David Hsu or JCE Software.