Hafnium

Base Information

• Chemical Name: Hafnium
• CAS No.: 7440-58-6
• Deprecated CAS: 412316-00-8
• Molecular Formula: Hf
• Molecular Weight: 178.49
• Hs Code.: 3822 00 00
• European Community (EC) Number: 231-166-4
• ICSC Number: 0847
• UN Number: 2545,1326
• UNII: X71938L1DO
• DSSTox Substance ID: DTXSID8064698
• Nikkaji Number: J14.779F,J399.364G
• Wikipedia: Hafnium
• Wikidata: Q1119
• NCI Thesaurus Code: C99317
• Mol file: 7440-58-6.mol

Synonyms:Hafnium

Chemical Property of Hafnium

Chemical Property:

• Appearance/Colour: solid
• Melting Point: 2227 °C(lit.)
• Boiling Point: 4602 °C(lit.)
• PSA: 0.00000
• Density: 13.31 g/cm³
• LogP: 0.00000
• Storage Temp.: Store at +15°C to +25°C.
• Water Solubility.: soluble HF; slowly reacts with conc H2SO4, aqua regia [KIR80]
• Hydrogen Bond Donor Count: 0
• Hydrogen Bond Acceptor Count: 0
• Rotatable Bond Count: 0
• Exact Mass: 179.94656
• Heavy Atom Count: 1
• Complexity: 0
• Transport DOT Label: Spontaneously Combustible

Purity/Quality:

99.9% ^*data from raw suppliers

Hafnium foil, 6mm disks, thickness 0.5mm, annealed, 97% ^*data from reagent suppliers

Safty Information:

• Pictogram(s): F,Xn
• Hazard Codes: F,Xn,T
• Statements: 11-20/21/22-34-23/24/25
• Safety Statements: 9-16-26-27-33-36-36/37/39-45-28

MSDS Files:

SDS file from LookChem

Total 1 MSDS from other Authors

Useful:

• Chemical Classes: Metals -> Elements, Metallic
• Canonical SMILES: [Hf]
• Effects of Short Term Exposure: May cause mechanical irritation to the eyes, skin and respiratory tract.
• Physical Properties: Occurs as a close-packed hexagonal alpha-form and a body-centered cubic beta modification; electrical resistivity 35.5 microhm-cm at 20°C; magnetic susceptibility 0.42x10–6 emu/g at 25°C; thermal neutron absorption cross section 105 barns/atom; work function 3.5 eV; modulus of elasticity 20x106 psi; tensile strength 58,000 psi at 25°C; insoluble in water, dilute mineral acids and nitric acid at all concentrations; soluble in hydrofluoric acid, concentrated sulfuric acid and aqua regia.
• Uses: Hafnium use is limited due to low abundance. The primary use of hafnium is in the nuclear industry, where it is used in fuel rods to regulate fission given its high neutron absorption cross section. Similar to zirconium, hafnium is alloyed with niobium and carbide to produce high temperature refractory materials for furnaces and jet components as well as for plasma cutters. In addition, hafnium oxide is increasingly being used to augment or replace silicone oxidebased microprocessor chips in certain applications as well as in cathodes and capacitors (Field et al., 2011). Hafnium has a great affinity for absorbing slow neutrons. This attribute, along with itsstrength and resistance to corrosion, makes it superior to cadmium, which is also used formaking control rods for nuclear reactors. This use is of particular importance for the type ofnuclear reactors used aboard submarines. By moving the control rods in and out of a nuclearreactor, the fission chain reaction can be controlled as the neutrons are absorbed in the metalof the rods. The drawback to hafnium control rods is their expense: it costs approximately onemillion dollars for several dozen rods for use in a single nuclear reactor.In vacuum tubes and other applications that must have gases removed, hafnium is used asa “getter” to absorb any trace oxygen or nitrogen in the tube, thus extending the life of thevacuum tube. Hafnium’s qualities also make it ideal for filaments in light bulbs and, whenmixed with rare-earth metals, as a “sparking” misch metal. Hafnium is also used to a lesserextent as an alloying agent for several other metals, including iron, titanium, and niobium. Obtained in mining and purification of the metal; used in control rods in nuclear reactors and in manufacture of light bulb filaments; found in all zirconiumcontaining minerals
• Physical properties: Hafnium is a ductile metal that looks and feels much like stainless steel, but it is significantlyheavier than steel. When freshly cut, metallic hafnium has a bright silvery shine. Whenthe fresh surface is exposed to air, it rapidly forms a protective oxidized coating on its surface.Therefore, once oxidized, hafnium resists corrosion, as do most transition metals, whenexposed to the air. Chemically and physically, hafnium is very similar to zirconium, whichis located just above it in group 4 on the periodic table. In fact, they are so similar that it isalmost impossible to secure a pure sample of either one without a small percentage of theother. Each will contain a small amount of the other metal after final refining.Hafnium’s melting point is 2,227°C, its boiling point varies from about 2,500°C to5,000°C depending on its purity, and its density is 13.29 g/cm3. The compound hafniumnitride (HfN) has the highest melting point (over 3,300°C) of any two-element compound.