Hafnium

Definition: Hafnium

Hafnium

Noun

1. A gray tetravalent metallic element that resembles zirconium chemically and is found in zirconium minerals; used in filaments for its ready emission of electrons.

Specialty Definitions: Hafnium

Domain	Definitions
Industry	Obtained as by-product of metals and not extracted directly from one particular are. Source: European Union. (references)
Chemistry	Chemical element:atomic number 72. Source: European Union. (references)
Source: compiled by the editor from various references; see credits.

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Specialty Definition: Hafnium

(From Wikipedia, the free Encyclopedia)

Lutetium - Hafnium - Tantalum
Zr Hf Rf
	Full table

General

Name, Symbol, Number

Hafnium, Hf, 72

Chemical series

Transition metals

Group, Period, Block

4 (IVB), 6 , d

Density, Hardness

13310 kg/m³, 5.5

Appearance

grey steel

Atomic Properties

Atomic weight

178.49 amu

Atomic radius (calc.)

155 (208) pm

Covalent radius

150 pm

van der Waals radius

no data

Electron configuration

[Xe]44f¹⁴ 5d² 6s²

e^- 's per energy level

2, 8, 18, 32, 10, 2

Oxidation state (Oxide)

4 (amphoteric)

Crystal structure

Hexagonal

Physical Properties

State of matter

solid

Melting point

2506 K (4051 °F)

Boiling point

4876 K (8317 °F)

Molar volume

13.44 ×1010^-3 m³/mol

Heat of vaporization

575 kJ/mol

Heat of fusion

24.06 kJ/mol

Vapor pressure

0.00112Pa at 2500K

Speed of sound

3010 m/s at 293.15 K

Miscellaneous

Electronegativity

1.3 (Pauling scale)

Specific heat capacity

140 J/(kg*K)

Electrical conductivity

3.12 10⁶/m ohm

Thermal conductivity

23 W/(m*K)

1^st ionization potential

658.5 kJ/mol

2^nd ionization potential

1440 kJ/mol

Most Stable Isotopes

iso	NA	half-life	DM	DE MeV	DP
¹⁷²Hf	{syn.}	1.87 y	&epsilon	0.350	¹⁷²Lu
¹⁷⁴Hf	0.162%	2 E15 y	&alpha	2.495	¹⁷⁰Yb
¹⁷⁶Hf	5.206%	Hf is stable with 104 neutrons
¹⁷⁷Hf	18.606%	Hf is stable with 105 neutrons
¹⁷⁸Hf	27.297%	Hf is stable with 106 neutrons
¹⁷⁹Hf	13.629%	Hf is stable with 107 neutrons
¹⁸⁰Hf	35.1%	Hf is stable with 108 neutrons
¹⁸²Hf	{syn}	9 E6 y	&beta	0.373	¹⁸²Ta

SI units & STP are used except where noted.

Hafnium is a chemical element in the periodic table that has the symbol Hf and atomic number 72. A lustrous, silvery gray tetravalent transition metal, hafnium resembles zirconium chemically and is found in zirconium minerals. Hafnium is used in tungsten alloys in filaments and electrodes and also acts as a neutron absorber in nuclear control rods.

Notable Characteristics

This is a shiny silvery, ductile metal that is corrosion resistant and chemically similar to zirconium. The properties of hafnium are markedly affected by zirconium impurities and these two elements are amongst the most difficult to separate. The only notable difference between them is their density (zirconium is about half as dense as hafnium).

Hafnium carbide is the most refractory binary compound known and hafnium nitride is the most refractory of all known metal nitrides with a melting point of 3310 °C). This metal is resistant to concentrated alkalis, but halogens react with it to form hafnium tetrahalides. At higher temperatures hafnium reacts with oxygen, nitrogen, carbon, boron, sulfur, and silicon.

The nuclear isomer Hf-178-2m is also a source of energetic gamma rays, and is being studied as a possible power source for gamma ray lasers.

Applications

Hafnium is used to make nuclear control rods, such as those found in nuclear submarines because of its ability to absorb neutrons (its thermal neutron absorption cross section is nearly 600 times that of zirconium), excellent mechanical properties and exceptional corrosion-resistance properties. Other uses;

Used in gas-filled and incandescent lamps,
for scavenging oxygen and nitrogen,
and in iron, titanium, niobium, tantalum, and other metal alloys.

History

Hafnium (Latin Hafnia\ for "Copenhagen") was discovered by Dirk Coster and Georg von Hevesy in 1923 in Copenhagen, Denmark. Soon after, the new element was predicted to be associated with zirconium by using the Bohr theory and was finally found in zircon through X-ray spectroscope analysis in Norway.

It was separated from zirconium through repeated recrystallization of double ammonium or potassium fluorides by Jantzen and von Hevesey. Metallic hafnium was first prepared by Anton Eduard van Arkel and Jan Hendrik deBoer by passing the tetraiodide vapor over a heated tungsten filament.

Occurrence

Hafnium is found combined in natural zirconium compounds but it is never found as a free element in nature. Minerals that contain zirconium, such as alvite [(Hf, Th, Zr)SiO₄ H₂O], thortveitite and zircon (ZrSiO₄), usually contain 1 and 5 percent hafnium. Hafnium and zirconium have nearly identical chemistry, which makes the two difficult to separate. About half of all hafnium metal manufactured is produced by a by-product of zirconium refinement. This is done through reducing hafnium tetrachloride with magnesium or sodium in the Kroll Process.

Precautions

Care needs to be taken when machining hafnium because when it is divided into fine particles, it is pyrophoric and can ignite spontaneously in air. Compounds that contain this metal are rarely encountered by most people and the pure metal is not normally toxic but all its compounds should be handled as if they are toxic (although there appears to be limited danger to exposed individuals).

External Links

Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Hafnium."

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Synonym: Hafnium

Synonym: atomic number 72 (n). (additional references)

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Crosswords: Hafnium

English words defined with "hafnium": George Charles Hevesy de Hevesy ♦ Hevesy. (references)

Specialty definitions using "hafnium": beryllides ♦ crystal bar ♦ hafnium silicate ♦ iodide metal ♦ zirconium minerals. (references)

Non-English Usage: "Hafnium" is also a word in the following languages with English translations in parentheses.

Albanian (hafnium), Czech (hafnium), Dutch (hafnium), French (hafnium), German (hafnium), Hungarian (hafnium).

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Commercial Usage: Hafnium

Domain	Title
Books	Analytical chemistry of zirconium and hafnium (reference) Astm Manual on Zirconium and Hafnium (reference) Chemistry of Organo-Zirconium and Hafnium Compounds (reference) Comprehensive Organometallic Chemistry II: Scandium, Yttrium, Lanthanides and Actinides, and Titanium, Zirconium, and Hafnium (reference) Hafnium in Nuclear Engineering (Russian Materials Monograph Series) (reference) (more book examples)
Source: compiled by the editor from various references; see credits.

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Frequency of Internet Keywords: Hafnium

The following statistics estimate the number of searches per day across the major English-language search engines as identified by various trade publications. Hyperlinks lead to commercial use of the expression at Amazon.com.

Expression	Frequency per Day
hafnium	30
hafnium oxide	5
hafnium information	4
chloride hafnium	4
alloy hafnium	3
hafnium oxychloride	3
hafnium hydride	3
etching hafnium	2
hafnium oxynitrate	2
Source: compiled by the editor from various references; see credits.

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Modern Translations: Hafnium

Language		Translations for "hafnium"; alternative meanings/domain in parentheses.
Albanian		hafnium. (various references)

Arabic		‏الهفنيوم عنصر فلزي. (various references)

Bulgarian		хафний. (various references)

Chinese		鉿 , �"�. (various references)

Czech		hafnium. (various references)

Danish		hafnium, celtium. (various references)

Dutch		hafnium. (various references)

Esperanto		hafnio. (various references)

French		hafnium. (various references)

German		hafnium. (various references)

Greek		άφνιο. (various references)

Hungarian		hafnium. (various references)

Italian		afnio. (various references)

Japanese Kanji		ハトロン紙 (agreed, Armageddon, falling rapidly in big drops, good, haddock, halation, halberd, Halley, ham, ham and eggs, ham and salad, Hamilton, Hamming, Hammond organ, hamster, Hanoi, happening, Harrier, Harry, hashed meat with rice, heart going pit-a-pat, honey, honeymoon, Honeywell, Hubbard, hum, humming, hurricane, kraft paper, resin, rosefish, splendid, style of clothing popular in the late 1970s and resembling a Catholic school uniform, to be in harmony, to harmonize, twitterpating, wonderful). (various references)

Japanese Katakana		ハフニウ� . (various references)

Pig Latin		afniumhay.(various references)

Portuguese		hemostático (haemostatic preparation, hemp, styptic), háfnio (haft). (various references)

Russian		гафний. (various references)

Spanish		hafnio. (various references)

Thai		ธาตุโลหะชนิ�"หนึ่งที่มี 4 วาเลนซี มีสัญลักษ�"์ Hf. (various references)

Turkish		hafniyum. (various references)

Ukranian		гафній. (various references)
Source: compiled by the editor from various translation references.

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Derivations & Misspellings: Hafnium

Derivations
	Words beginning with "hafnium": hafniums. (additional references)
Misspellings
	"Hafnium" is suggested in spellcheckers for the following: annium, Hafina, Hanim, Hanoun, Haynau, khanoum. (additional references)
Source: compiled by the editor, based on several corpora (additional references).

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Rhyming with "Hafnium"

# of Phoneme Matches	Pronunciation	Word(s) rhyming with "hafnium" (pronounced ha"fnēum)
4	-n ē u m	ammonium, condominium, geranium, gonium, harmonium, millennium, minium, neptunium, pandemonium, plutonium, polonium, selenium, titanium, uranium, zirconium.
3	-ē u m	alluvium, aquarium, atrium, auditorium, axiom, bacterium, barium, beryllium, cadmium, calcium, cesium, chromium, colloquium, compendium, consortium, crematorium, delirium, deuterium, disequilibrium, emporium, equilibrium, europium, fermium, gallium, gymnasium, helium, Herbarium, holmium, honorarium, idiom, indium, iridium, lawrencium, linoleum, lithium, magnesium, medium, moratorium, myocardium, nephridium, niobium, nobelium, opium, opprobrium, osmium, palladium, paramecium, petroleum, planetarium, Plasmodium, podium, potassium, premium, presidium, promethium, protium, psyllium, radium, requiem, rhodium, sodium, stadium, strontium, superpremium, symposium, tedium, tellurium, thallium, thorium, tritium, vanadium, yttrium.
Source: compiled by the editor (additional references); see credits.

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Anagrams: Hafnium

Scrabble® Enable2K-Verified Anagrams
	Words within the letters "a-f-h-i-m-n-u"
	-2 letters: fanum, human.
	-3 letters: amin, fain, faun, main, maun, mina, muni, naif, unai.
	-4 letters: aim, ain, ami, amu, ani, fan, fin, fun, ham, him, hin, hum, hun, man, mun, nah, nam, nim.
	-5 letters: ah, ai, am, an, fa, ha, hi, hm, if, in, ma, mi, mu, na, nu, uh, um, un.
	Words containing the letters "a-f-h-i-m-n-u"
	+1 letter: hafniums.
	+3 letters: infrahuman.
	+4 letters: infrahumans.
	+5 letters: humification.
Source: compiled by the editor from various references; see credits. SCRABBLE® is a registered trademark. All intellectual property rights in and to the game are owned in the U.S.A and Canada by Hasbro Inc., and throughout the rest of the world by J.W. Spear & Sons Limited of Maidenhead, Berkshire, England, a subsidiary of Mattel Inc. Mattel and Spear are not affiliated with Hasbro.