Wolfram (W)

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Wolfram 74W183.85


1783 von J.J. und F. Elhuijar in Vergara, Spanien, dargestellt.

[Der englische Name tungsten kommt vom Schwedischen tung sten = schwerer Stein; Wolfram kommt vom Mineral Wolframit]

French: tungstène
German: wolfram
Italian: wolframio (tungsteno)
Spanish: wolframio


Beschreibung: Man erhält es als mattgraues Pulver, das schwer zu schmelzen ist. Das Metall ist glänzend und silberweiß. Durch Sauerstoff, Säuren und Alkalien wird es nicht angegriffen. Verwendung für Legierungen, Glühdrähte und Schneidwerkzeuge.

  

Wolfram single crystal properties

State: single crystal
Crystal structure: bcc
Production method: Floating zone
Standard size: diameter 8-12mm
thickness 1-2mm
Orientation: (100), (110) and (111)
Orientation accuracy: <2°, <1°, <0.4° or <0.1°
Polishing: as cut, one or two sides polished
Roughness of surface: <0.03µm
Purity: 99.999%
Typical analysis (ppm): C 3
H < 1
O 9
N < 5
Cu 1.60
Fe 1.80
Ni < 1
Pb 0.30
Si 0.30

 
Ga, Hf and Ta are below the detection limit
 

Materials properties

Density: 19.3 g/cm3
Melting point: 3406.85±20 °C / 3680±20 °K
Boiling point: 5656.85 °C / 5930 °K
Molar volume: 9.53 cm3
Thermal conductivity: 174 [300 K] Wm-1K-1
Coefficient of linear thermal expansion: 4.59 x 10-6 K-1
Electrical resistivity: 5.65x 10-8 [300 K] Wm
Mass magnetic susceptibility: +4.0 x 10-9(s) kg-1m3
Young's modulus: 411 GPa
Rigidity modulus: 160.6 GPa
Bulk modulus: 311 GPa
Poisson's ratio: 0.28 GPa
Radii: W6+ 62; W4+ 68; atomic 137; covalent 130
Electronegativity: 2.36 (Pauling); 1.40 (Allred); 4.40 eV (absolute)
Effective nuclear charge: 4.35 (Slater); 9.85 (Clementi); 14.22 (Froese-Fischer)
Number of Isotopes (incl. nuclear isomers): 29
Issotope mass range: 160 -> 190
Crystal structure, (cell dimentions / pm), space group bcc
X-ray diffraction: mass absorption coefficients: CuKα 172 (µ/r) / cm2g-1
MoKα 99.1 (µ/r) / cm2g-1
Neutron scattering length: 0.486 b/10-12 cm
Thermal neutron capture cross-section: 18.3 sa / barns

 


Biological data

Biological role: none
Toxicity  
Toxic intake: mildly toxic
Lethal intake: LD50 (metal, rat) = 2000 mg kg-1
Hazards: Tungsten dust is a skin and eye irritant and an experimental teratogen.
Level in humans  
Blood: 0.001 mg dm-3
Bone: 0.00025 p.p.m.
Liver: n.a.
Muscle: n.a.
Daily dietary intake: 0.001 - 0.015 mg
Total mass of element in average [70 kg] person: c. 0.02 mg

 


Geological data

MineralFormulaDensityHardnessCrystal apperance
Ferberite FeWO4 7.40 4 - 4.5 mon., met. black
Scheelite CaWO4 6.10 4.5 5 tet., vit./adam. colourless
Wolframite (Fe, Mn) WO4 7.3 4 - 4.5 mon., sub-met./adam. greyish-black

 

Chief ore: scheelite and wolframite
World production: 45 100 tonnes/year
Main mining areas: China, Malaysia, Burma, Bolivia, Canada, Australia, Japan, USA
Reserves: 1.5 x 106 tonnes
Specimen: available as foil, powder, rod or wire. Safe.

 

Abundances  
Sun: 50 (relative to H = 1 x 1012)
Earth's crust: 1 p.p.m.
Seawater:  
Residence time:  
Classification:  
Oxidation state: VI

Übersicht der Elemente mit Zugang zu unserem Shop

1 18
H
2 13 14 15 16 17
He
Li Be B C
N
O
F
Ne
Na Mg 3 4 5 6 7 8 9 10 11 12 Al Si P S
Cl
Ar
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se
Br
Kr
Rb Sr Y Zr Nb Mo
Tc
Ru Rh Pd Ag Cd In Sn Sb Te I
Xe
Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi
Po
At
Ra
Fr
Ra
Ac
Ce Pr Nd
Pm
Sm Eu Gd Tb Dy Ho Er Tm Yb Lu


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