| Identification | More | [Name]
HAFNIUM OXIDE | [CAS]
12055-23-1 | [Synonyms]
HAFNIUM(+4)OXIDE
HAFNIUM(IV) OXIDE
HAFNIUM OXIDE
Hafnia
Hafnium oxide (HfO2)
hafniumoxide(hfo2)
HfO2
Hafniumoxideoffwhitepowder
Hafniumoxidesinteredlumps
HAFFNIUM (IV) OXIDE 99%
HAFNIUM OXIDE, 99.95+%
HAFNIUM OXIDE, POWDER,98%
HAFNIUM (IV) OXIDE 98%
HAFNIUM (IV) OXIDE 99.99% (METALS BASIS)
HAFNIUM (IV) OXIDE 99.999% (METAL BASIS) SPECTRO
HAFNIUM (IV) OXIDE 99.9% (METALS BASIS)
HAFNIUM OXIDE, 99.9%
Hafnium(IV)oxide(99.995%-Hf,<0.15%Zr)PURATREM
Hafnium(IV)oxide,98%
hafnium(iv) oxide, spectrographic grade | [EINECS(EC#)]
235-013-2 | [Molecular Formula]
HfO2 | [MDL Number]
MFCD00003565 | [Molecular Weight]
210.49 | [MOL File]
12055-23-1.mol |
| Chemical Properties | Back Directory | [Description]
Hafnium is a shiny, silvery, ductile metal and resistant to corrosion. The physical properties
of hafnium metal samples are markedly affected by zirconium impurities, especially
the nuclear properties, as these two elements are among the most difficult to separate
because of their chemical similarity.
Hafnia is used in optical coatings and as a high-k dielectric in dynamic randomaccess
memory (DRAM) capacitors. Hafnium (IV) oxide is a colourless, inert solid and
has been reported as one of the most common and stable compounds of hafnium. It is
an electrical insulator. Hafnium dioxide is an intermediate in some processes that give
hafnium metal. It reacts with strong acids and strong bases. It dissolves slowly in hydrofluoric
acid. At high temperatures, it reacts with chlorine in the presence of graphite or
carbon tetrachloride and forms the hafnium tetrachloride. Hafnium-based oxides are
currently important materials to replace silicon oxide as a gate insulator because of its
high dielectric constant.
Hafnium (Hf) is found in association with zirconium ores, production based on zircon
(ZrSiO4) concentrates which contain 0.5%–2% hafnium. Hafnium has extensive applications
in industries especially because of its resistance to corrosion. Different compounds
of hafnium used in ceramics industry are hafnium boride, hafnium carbide, hafnium
nitride, hafnium oxide, hafnium silicate, and hafnium titanate. Hafnium-based oxides
are currently leading candidates to replace silicon oxide as a gate insulator in fieldeffect
transistors. The compound appears to have been chosen by both IBM and Intel
as a substrate for future integrated circuits, where it may help in the continuing effort | [Appearance]
Hafnium is a refractory metal which occurs in
nature in zirconium minerals. | [Melting point ]
2810 °C
| [density ]
9.68 g/mL at 25 °C(lit.)
| [refractive index ]
2.13 (1700 nm) | [solubility ]
insoluble in H2O | [form ]
powder
| [color ]
Off-white | [Specific Gravity]
9.68 | [Water Solubility ]
Insoluble in water. | [Crystal Structure]
Monoclinic | [Merck ]
14,4588 | [Exposure limits]
ACGIH: TWA 0.5 mg/m3
NIOSH: IDLH 50 mg/m3; TWA 0.5 mg/m3 | [InChIKey]
CJNBYAVZURUTKZ-UHFFFAOYSA-N | [CAS DataBase Reference]
12055-23-1(CAS DataBase Reference) | [EPA Substance Registry System]
Hafnium oxide (HfO2) (12055-23-1) |
| Safety Data | Back Directory | [Safety Statements ]
S22:Do not breathe dust .
S24/25:Avoid contact with skin and eyes . | [WGK Germany ]
3
| [TSCA ]
Yes | [HS Code ]
28259085 |
| Hazard Information | Back Directory | [Potential Exposure]
Hafnium metal has been used as a
control rod material in nuclear reactors. Thus, those
engaged in fabrication and machining of such rods may be
exposed. | [First aid]
If this chemical gets into the eyes, remove any
contact lenses at once and irrigate immediately for at least
15 minutes, occasionally lifting upper and lower lids. Seek
medical attention immediately. If this chemical contacts the
skin, remove contaminated clothing and wash immediately
with soap and water. Seek medical attention immediately.
If this chemical has been inhaled, remove from exposure,
begin rescue breathing (using universal precautions, includ ing resuscitation mask) if breathing has stopped and CPR if
heart action has stopped. Transfer promptly to a medical
facility. When this chemical has been swallowed, get medi cal attention. Give large quantities of water and induce
vomiting. Do not make an unconscious person vomit. | [Shipping]
UN1326 Hafnium powder, wetted with not
<,25% water (a visible excess of water must be present)
(1) mechanically produced, particle size<53 μm; (2)
chemically produced, particle size<840 μm, Hazard Class:
4.1; Labels: 4.1-Flammable solid. UN2545 Hafnium pow der, dry, Hazard Class: 4.1; Labels: 4.1-Flammable solid.
UN1346 Hafnium powder, wetted with not less than 25%
water (a visible excess of water must be present)
(1) mechanically produced, particle size less than 53 μm;
(2) chemically produced, particle size less than 840 μm,
Hazard Class: 4.1; Labels: 4.1-Flammable solid. | [Incompatibilities]
Fine powder or dust may form explosive
mixture in air. The powder is highly flammable and a strong
reducing agent. The powder or dust reacts with moisture
forming flammable hydrogen gas; may spontaneously ignite
on contact with moist air; and at higher temperatures, with
nitrogen, phosphorous, oxygen, halogens, and sulfur; contact
with hot nitric acid; heat, shock, friction, strong oxidizers;
or ignition sources may cause explosions. | [Chemical Properties]
Hafnium is a refractory metal which occurs in
nature in zirconium minerals. | [Waste Disposal]
Recovery. Consider recycling,
otherwise, this chemical must be disposed of in compliance
with existing federal and local regulations. | [Flammability and Explosibility]
Nonflammable |
| Questions And Answer | Back Directory | [Physical Properties]
White crystalline solid, when heated at 1,500°C, it transforms into a tetragonal modification with shrinkage; tetragonal form converts to a cubic polymorph with fluorite structure when heated at 2,700°C; density 9.68 g/cm3; melts at 2,774°C; insoluble in water; dissolves slowly in hydrofluoric acid at ordinary temperatures.
| [Uses]
Hafnium dioxide is a high temperature refractory material. It is used for control rods in nuclear reactors. It has high stability and high thermal neutron absorption values. It also is used in special optical glasses and glazes.
| [Preparation]
Hafnium dioxide may be prepared by heating the metal with air or oxygen at elevated temperatures (above 400°C). Also, the oxide can be obtained by igniting hafnium salts, such as hydroxide, oxalate, sulfate, nitride, carbide, boride or tetrachloride in air. Hafnium carbide converts to dioxide when heated with oxygen at 500°C. The commercial products generally contain about 95-97% hafnium dioxide mixed with small amount of zirconium oxide. The compound can be prepared at 99.9% purity.
| [Reactions]
Hafnium dioxide reacts with chlorine in the presence of carbon at elevated temperatures to yield hafnium tetrachloride, HfCl4. When ammonium hydroxide solution is added to an acid solution of hafnium dioxide, the hydrous oxide, HfO2•xH2O precipitates.
When heated with concentrated sulfuric acid, the product is hafnium sulfate, Hf(SO4)2.
Reaction with carbon at 1,500°C produces hafnium carbide, HfC.
Reaction with sodium fluorosilicate, Na2SiF6 at elevated temperatures yields sodium fluorohafnate, Na2HfF6.
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