Hafnium (Hf)

We are a leading manufacturer and supplier of research materials

Hafnium ₇₂Hf^178.49

Discovered in 1923 by D. Coster and G.C. von Hevesey at Copenhagen, Denmark.

[Latin: Hafnia = Copenhagen]
  French: hafnium
  German: hafnium
  Italian: afnio
  Spanish: hafnio

Description: Hafnium is a lustrous, silvery, ductile metal that resists corrision due to an oxide film on its surface. However, powdered hafnium will burn in air. The metal is unaffected by acids (exept HF) and alkalis. It is used in control rods for nuclear reactors, and in high temperature alloys and ceramics.

Hafnium single crystal properties

State:	Single crystal
Crystal structure:	hexagonal
Production method:	Floating zone
Standard size:	diameter 7-8mm thickness 1mm
Orientation:	(0001)
Orientation accuracy:	<2°, <1°, <0.4° or <0.1°
Polishing:	as cut, one or two sides polished
Roughness of surface:	<0.03 µm
Purity:	99.99%

Further Materials properties

Crystal structure:	(cell dimensions/pm), space group a-Hf h.c.p. (a=319.46, c=505.10), P63/mmc b-Hf cubic (a=362) T(a -> a)=2033 K
X-ray diffractions mass absorption coefficients:	CuKa 159 (µ/r) / cm2g-1 MoKa 91.7 (µ/r) / cm2g-1
Neutron scattering length:	0.777 b/10-12 cm
Thermal neutron capture cross-section:	104 sa / barns
Density:	13.1 kg/m-3 [293 K]; 2390 [liquid at m.p.]
Melting point:	2229.85 °C / 2503 °K
Boiling point:	5196.85 °C / 5470 °K
Molar volume:	13.41 cm3
Thermal conductivity:	23.0 [300 K] Wm-1K-1
Coefficient of linear thermal expansion:	5.9 x 10-6 K-1
Electrical resistivity:	35.1 x 10-8 [293 K] Wm
Mass magnetic susceptibility:	+5.3 x 10-9(s) kg-1m3
Young's modulus:	141 GPa
Rigidity modulus:	56 GPa
Bulk modulus:	109 GPa
Poisson's ratio:	0.26
Radi:	Hf3+ 84; atomic 156; covalent 144
Electronegativity:	1.3 (Pauling); 1.23 (Allred); 3.8 eV (absolute)
Effective nuclear charge:	3.15 (Slater); 9.16 (Clementi); 13.27 (Froese-Fischer)
Number of Isotopes (incl. nuclear isomers):	33
Isotope mass range:	158 -> 184

Biological data

Biological role:	none
Toxicity
Toxic intake:	hafnium and hafnium salts generally have low toxicity
Lethal intake:	LD50 (chloride, oral, rat)=2400 mg kg-1
Hazards:	Hafnium is poorly absorbed by the body and poisoning by hafnium compounds is very rare.
Level in humans
Organs:	n.a.
Daily dietary intake:	n.a.
Total mass of element in average [70 kg] person:	n.a.

Geological data

Minerals:	Many minerals are known, and aluminium is present in many other minerals
Mineral	Formula	Density	Hardness	Crystal apperance
Hafnon	HfSiO4	6.97	n.a.	tet.

Chief ore:	hafnium is obtained as a by-product of zirconium refining
World production:	c. 50 tonnes/year
Main mining areas:	see zirconium
Reserves:	n.a.
Specimen:	available as foil, pieces, powder sponge or wire. Safe.