Difference between revisions of "Tungsten"

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(Created page with "Tungsten filaments from a car light bulb compared to a 2 Euro cent coin. '''Tungsten''', also known as '''wolf...")
 
 
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[[File:Tungsten_filaments_and_2_cent_euro_coin.jpg|thumb|300px|Tungsten filaments from a car light bulb compared to a 2 Euro cent coin.]]
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{{Infobox element
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'''Tungsten''', also known as '''wolfram''', is a chemical element with the chemical symbol '''W''' and atomic number 74. It is a hard and heavy transitional metal.
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<!-- top -->
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|image name=Tungsten_filaments_and_2_cent_euro_coin.jpg
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|image alt=
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|image size=300
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|image name comment=Tungsten filaments from several car light bulbs, compared to a 2 Euro cent coin.
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|image name 2=
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|image alt 2=
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|image size 2=
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|image name 2 comment=
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<!-- General properties -->
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|name=Tungsten
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|symbol=W
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|pronounce=
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|pronounce ref=
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|pronounce comment=
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|pronounce 2=
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|alt name=Wolfram
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|alt names=
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|allotropes=
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|appearance=Silvery-gray
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<!-- Periodic table -->
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|above=[[Molybdenum|Mo]]
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|below=Sg
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|left=[[Tantalum]]
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|right=[[Rhenium]]
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|number=74
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|atomic mass=183.84(1)
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|atomic mass 2=
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|atomic mass ref=
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|atomic mass comment=
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|series=
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|series ref=
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|series comment=
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|series color=
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|group=6
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|group ref=
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|group comment=
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|period=6
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|period ref=
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|period comment=
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|block=d
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|block ref=
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|block comment=
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|electron configuration=[Xe] 4f<sup>14</sup> 5d<sup>4</sup> 6s<sup>2</sup>
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|electron configuration ref=
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|electron configuration comment=
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|electrons per shell=2, 8, 18, 32, 12, 2
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|electrons per shell ref=
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|electrons per shell comment=
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<!-- Physical properties -->
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|physical properties comment=
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|color=Silvery-white
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|phase=Solid
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|phase ref=
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|phase comment=
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|melting point K=3695
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|melting point C=3422
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|melting point F=​6192
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|melting point ref=
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|melting point comment=
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|boiling point K=6203
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|boiling point C=5930
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|boiling point F=​10706
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|boiling point ref=
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|boiling point comment=
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|sublimation point K=
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|sublimation point C=
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|sublimation point F=
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|sublimation point ref=
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|sublimation point comment=
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|density gplstp=
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|density gplstp ref=
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|density gplstp comment=
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|density gpcm3nrt=19.25
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|density gpcm3nrt ref=
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|density gpcm3nrt comment=
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|density gpcm3nrt 2=
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|density gpcm3nrt 2 ref=
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|density gpcm3nrt 2 comment=
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|density gpcm3nrt 3=
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|density gpcm3nrt 3 ref=
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|density gpcm3nrt 3 comment=
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|density gpcm3mp=17.6
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|density gpcm3mp ref=
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|density gpcm3mp comment=
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|density gpcm3bp=
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|density gpcm3bp ref=
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|density gpcm3bp comment=
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|molar volume=
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|molar volume unit =
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|molar volume ref=
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|molar volume comment=
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|triple point K=
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|triple point kPa=
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|triple point ref=
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|triple point comment=
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|triple point K 2=
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|triple point kPa 2=
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|triple point 2 ref=
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|triple point 2 comment=
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|critical point K=
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|critical point MPa=
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|critical point ref=
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|critical point comment=
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|heat fusion=52.31
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|heat fusion ref=
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|heat fusion comment=
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|heat fusion 2=
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|heat fusion 2 ref=
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|heat fusion 2 comment=
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|heat vaporization=774
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|heat vaporization ref=
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|heat vaporization comment=
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|heat capacity=24.27
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|heat capacity ref=
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|heat capacity comment=
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|heat capacity 2=
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|heat capacity 2 ref=
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|heat capacity 2 comment=
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|vapor pressure 1=3477
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|vapor pressure 10=3773
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|vapor pressure 100=4137
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|vapor pressure 1 k=4579
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|vapor pressure 10 k=5127
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|vapor pressure 100 k=5823
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|vapor pressure ref=
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|vapor pressure comment=
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|vapor pressure 1 2=
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|vapor pressure 10 2=
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|vapor pressure 100 2=
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|vapor pressure 1 k 2=
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|vapor pressure 10 k 2=
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|vapor pressure 100 k 2=
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|vapor pressure 2 ref=
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|vapor pressure 2 comment=
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<!-- Atomic properties -->
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|atomic properties comment=
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|oxidation states='''6''', 5, '''4''', 3, 2, 1, 0, −1, −2, −4
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|oxidation states ref=
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|oxidation states comment=​(a mildly acidic oxide)
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|electronegativity=2.36
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|electronegativity ref=
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|electronegativity comment=
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|ionization energy 1=770
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|ionization energy 1 ref=
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|ionization energy 1 comment=
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|ionization energy 2=1700
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|ionization energy 2 ref=
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|ionization energy 2 comment=
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|ionization energy 3=
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|ionization energy 3 ref=
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|ionization energy 3 comment=
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|number of ionization energies=
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|ionization energy ref=
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|ionization energy comment=
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|atomic radius=139
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|atomic radius ref=
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|atomic radius comment=
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|atomic radius calculated=
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|atomic radius calculated ref=
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|atomic radius calculated comment=
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|covalent radius=162±7
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|covalent radius ref=
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|covalent radius comment=
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|Van der Waals radius=
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|Van der Waals radius ref=
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|Van der Waals radius comment=
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<!-- Miscellanea -->
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|crystal structure=
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|crystal structure prefix=
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|crystal structure ref=
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|crystal structure comment=Body-centered cubic (bcc)
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|crystal structure 2=
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|crystal structure 2 prefix=
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|crystal structure 2 ref=
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|crystal structure 2 comment=
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|speed of sound=
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|speed of sound ref=
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|speed of sound comment=
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|speed of sound rod at 20=
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|speed of sound rod at 20 ref=
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|speed of sound rod at 20 comment=
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|speed of sound rod at r.t.=4620
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|speed of sound rod at r.t. ref=
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|speed of sound rod at r.t. comment=(annealed)
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|thermal expansion=
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|thermal expansion ref=
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|thermal expansion comment=
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|thermal expansion at 25=4.5
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|thermal expansion at 25 ref=
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|thermal expansion at 25 comment=
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|thermal conductivity=
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|thermal conductivity ref=
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|thermal conductivity comment=
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|thermal conductivity 2=
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|thermal conductivity 2 ref=
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|thermal conductivity 2 comment=
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|thermal diffusivity=
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|thermal diffusivity ref=
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|thermal diffusivity comment=
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|electrical resistivity=
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|electrical resistivity unit prefix=
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|electrical resistivity ref=
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|electrical resistivity comment=
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|electrical resistivity at 0=
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|electrical resistivity at 0 ref=
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|electrical resistivity at 0 comment=
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|electrical resistivity at 20=5.28·10<sup>-8</sup>
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|electrical resistivity at 20 ref=
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|electrical resistivity at 20 comment=
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|band gap=
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|band gap ref=
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|band gap comment=
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|Curie point K=
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|Curie point ref=
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|Curie point comment=
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|magnetic ordering=Paramagnetic
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|magnetic ordering ref=
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|magnetic ordering comment=
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|tensile strength=1510
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|tensile strength ref=
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|tensile strength comment=
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|Young's modulus=411
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|Young's modulus ref=
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|Young's modulus comment=
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|Shear modulus=161
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|Shear modulus ref=
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|Shear modulus comment=
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|Bulk modulus=310
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|Bulk modulus ref=
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|Bulk modulus comment=
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|Poisson ratio=0.28
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|Poisson ratio ref=
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|Poisson ratio comment=
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|Mohs hardness=7.5
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|Mohs hardness ref=
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|Mohs hardness comment=
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|Mohs hardness 2=
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|Mohs hardness 2 ref=
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|Mohs hardness 2 comment=
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|Vickers hardness=3430–4600
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|Vickers hardness ref=
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|Vickers hardness comment=
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|Brinell hardness=2000–4000
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|Brinell hardness ref=
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|Brinell hardness comment=
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|CAS number=7440-33-7
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|CAS number ref=
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|CAS number comment=
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<!-- History -->
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|naming=
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|predicted by=
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|prediction date ref=
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|prediction date=
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|discovered by=Carl Wilhelm Scheele
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|discovery date ref=
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|discovery date=1781
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|first isolation by=Juan José Elhuyar and Fausto Elhuyar
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|first isolation date ref=
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|first isolation date=1783
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|discovery and first isolation by=
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|named by= Torbern Bergman
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|named date ref=
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|named date=1781
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|history comment label=
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|history comment=
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<!-- Isotopes -->
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|isotopes=
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|isotopes comment=
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|engvar=
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}}
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'''Tungsten''', also known as '''wolfram''', is a chemical element with the chemical symbol '''W''' and atomic number 74. It is a hard and heavy transitional metal. Main ore of tungsten is ''wolframite''.
 +
 
 +
Tungsten in its elemental form is very rare in nature, it was found only in very small quantities in Bol'shaya Pol'ya River, Subarctic Urals, Russia and On Luna 16 landing site, The Moon.
  
 
==Properties==
 
==Properties==
 
===Chemical===
 
===Chemical===
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Elemental tungsten is resistant to [[oxygen]], acid, and alkali attacks at standard conditions. At very high temperatures tungsten will react with oxygen to produce [[tungsten trioxide]], a dense yellow chemical compound. This can be done by accident when burning light bulbs are broken and their hot filament is exposed to atmospheric oxygen. The trioxide dissolves in aqueous alkaline solutions to form tungstate ions. [[Tungsten carbide]]s (W<sub>2</sub>C and WC) are produced by heating powdered tungsten with carbon.
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Elemental tungsten is resistant to [[oxygen]], acid, and alkali attacks at standard conditions. At room temperature, tungsten reacts with concentrated [[hydrogen peroxide]]. At very high temperatures, tungsten will react with oxygen to produce [[tungsten trioxide]], a dense yellow chemical compound. This can be done by accident when burning light bulbs are broken and their hot filament is exposed to atmospheric oxygen. The trioxide dissolves in aqueous alkaline solutions to form tungstate ions. [[Tungsten carbide]]s (W<sub>2</sub>C and WC) are produced by heating powdered tungsten with carbon.
  
 
Tungsten reacts with [[fluorine]] gas at 350-400 °C to produce [[tungsten hexafluoride]]. This is one of the heaviest gas known, and it's sensitive to water, releasing [[hydrofluoric acid]]. It is mainly used in depositing extremely pure tungsten metal in chemical vapor deposition processes in semiconductor industry.
 
Tungsten reacts with [[fluorine]] gas at 350-400 °C to produce [[tungsten hexafluoride]]. This is one of the heaviest gas known, and it's sensitive to water, releasing [[hydrofluoric acid]]. It is mainly used in depositing extremely pure tungsten metal in chemical vapor deposition processes in semiconductor industry.
 +
 +
Alkali tungstates may be prepared in an electrolytic cell using tungsten as a cathode with an alkali metal hydroxide solution as an electrolyte.
  
 
===Physical===
 
===Physical===
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==Availability==
 
==Availability==
−
Tungsten can be obtained from light bulbs, in the form of filaments. However one would need a very large quantity of light bulbs to obtain a few grams, even thought the metal itself is very dense. Tungsten powder can be bought from chemical suppliers, however one should be checking its composition carefully to avoid buying its carbide, as "tungsten powder" is sometimes short for "tungsten carbide powder".
+
Tungsten can be obtained from light bulbs, in the form of filaments. However one would need a very large quantity of light bulbs to obtain a few grams, even thought the metal itself is very dense. About 2-300 incandescent light bulbs will yield like 4-5 grams of tungsten. Tungsten powder can be bought from chemical suppliers, however one should be checking its composition carefully to avoid buying its carbide, as "tungsten powder" is sometimes short for "tungsten carbide powder". It can also be bought as bars as well as wire.
−
It can also be bought as bars as well as wire.
+
  
−
Tungsten metal can also be found in welding rods. Pure tungsten rods are rare but do exist. More often, however, they have small amounts of thorium or a rare earth metal in their composition.
+
Tungsten metal can also be found in welding rods. Pure tungsten rods are rare but do exist. More often, however, they have small amounts of [[thorium]] or a rare earth metal in their composition.
  
 
Certain fishing weights are made of tungsten or tungsten alloyed with other heavy metals. These tend to be quite common in California, where tungsten is mined and lead products are sought to be replaced.
 
Certain fishing weights are made of tungsten or tungsten alloyed with other heavy metals. These tend to be quite common in California, where tungsten is mined and lead products are sought to be replaced.
  
−
==Preparation==
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==Isolation==
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Elemental tungsten can be prepared by reducing its oxide with [[carbon]] or [[hydrogen]]. It can also be prepared via thermal decomposition of the hexafluoride or reducing it with hydrogen. The latter method produces a very pure metal.
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Elemental tungsten can be prepared by reducing its oxide with [[carbon]] or [[hydrogen]]. Carbon reduction will generate some tungsten carbide, which will cause the metal to be brittle when sintered. It can also be prepared via thermal decomposition of the hexafluoride or reducing it with hydrogen. The latter method produces a very pure metal.
  
 
==Projects==
 
==Projects==
 
*Making tungsten trioxide
 
*Making tungsten trioxide
 
*Tungsten crucible for growing crystals
 
*Tungsten crucible for growing crystals
 +
*Synthesizing alkali metal tungstates
  
 
==Handling==
 
==Handling==
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===Storage===
 
===Storage===
−
No special storage is required for tungsten.
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No special storage is required for tungsten in bulk form. Powdered tungsten should be stored in closed bottles, away from draft. As it is very dense, use thick or tough containers for storage, as the container might deform when handled too often.  
  
 
===Disposal===
 
===Disposal===
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==References==
 
==References==
 
<references />
 
<references />
 +
*[http://www.mindat.org/min-7982.html Mindat]
 
===Relevant Sciencemadness threads===
 
===Relevant Sciencemadness threads===
 
*[http://www.sciencemadness.org/talk/viewthread.php?tid=16720 Recover Tungsten From Tungsten Carbide Scrap]
 
*[http://www.sciencemadness.org/talk/viewthread.php?tid=16720 Recover Tungsten From Tungsten Carbide Scrap]
 +
*[http://www.sciencemadness.org/talk/viewthread.php?tid=153266 Tungsten metal plus piranha solution?]
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[[Category:Elements]]
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[[Category:Metals]]
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[[Category:Transition metals]]
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[[Category:Refractory metals]]
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[[Category:D-block]]
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[[Category:Minerals]]
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[[Category:Noble metals]]

Latest revision as of 14:02, 8 April 2020

Tungsten,  74W
Tungsten filaments and 2 cent euro coin.jpg
Tungsten filaments from several car light bulbs, compared to a 2 Euro cent coin.
General properties
Name, symbol Tungsten, W
Alternative name Wolfram
Appearance Silvery-gray
Tungsten in the periodic table
Mo
↑
W
↓
Sg
Tantalum ← Tungsten → Rhenium
Atomic number 74
Standard atomic weight (Ar) 183.84(1)
Group, block , d-block
Period period 6
Electron configuration [Xe] 4f14 5d4 6s2
per shell
 2, 8, 18, 32, 12, 2
Physical properties
Silvery-white
Phase Solid
Melting point 3695 K ​(3422 °C, ​​6192 °F)
Boiling point 6203 K ​(5930 °C, ​​10706 °F)
Density near r.t. 19.25 g/cm3
when liquid, at  17.6 g/cm3
Heat of fusion 52.31 kJ/mol
Heat of 774 kJ/mol
Molar heat capacity 24.27 J/(mol·K)
 pressure
Atomic properties
Oxidation states 6, 5, 4, 3, 2, 1, 0, −1, −2, −4 ​​(a mildly acidic oxide)
Electronegativity Pauling scale: 2.36
energies 1st: 770 kJ/mol
2nd: 1700 kJ/mol
Atomic radius empirical: 139 pm
Covalent radius 162±7 pm
Miscellanea
Crystal structure ​Body-centered cubic (bcc)
Speed of sound thin rod 4620 m/s (at ) (annealed)
Thermal expansion 4.5 µm/(m·K) (at 25 °C)
Electrical resistivity 5.28·10-8 Ω·m (at 20 °C)
Magnetic ordering Paramagnetic
Tensile strength 1510 MPa
Young's modulus 411 GPa
Shear modulus 161 GPa
Bulk modulus 310 GPa
Poisson ratio 0.28
Mohs hardness 7.5
Vickers hardness 3430–4600 MPa
Brinell hardness 2000–4000 MPa
CAS Registry Number 7440-33-7
History
Discovery Carl Wilhelm Scheele (1781)
First isolation Juan José Elhuyar and Fausto Elhuyar (1783)
Named by Torbern Bergman (1781)
· references

Tungsten, also known as wolfram, is a chemical element with the chemical symbol W and atomic number 74. It is a hard and heavy transitional metal. Main ore of tungsten is wolframite.

Tungsten in its elemental form is very rare in nature, it was found only in very small quantities in Bol'shaya Pol'ya River, Subarctic Urals, Russia and On Luna 16 landing site, The Moon.

Properties

Chemical

Elemental tungsten is resistant to oxygen, acid, and alkali attacks at standard conditions. At room temperature, tungsten reacts with concentrated hydrogen peroxide. At very high temperatures, tungsten will react with oxygen to produce tungsten trioxide, a dense yellow chemical compound. This can be done by accident when burning light bulbs are broken and their hot filament is exposed to atmospheric oxygen. The trioxide dissolves in aqueous alkaline solutions to form tungstate ions. Tungsten carbides (W2C and WC) are produced by heating powdered tungsten with carbon.

Tungsten reacts with fluorine gas at 350-400 °C to produce tungsten hexafluoride. This is one of the heaviest gas known, and it's sensitive to water, releasing hydrofluoric acid. It is mainly used in depositing extremely pure tungsten metal in chemical vapor deposition processes in semiconductor industry.

Alkali tungstates may be prepared in an electrolytic cell using tungsten as a cathode with an alkali metal hydroxide solution as an electrolyte.

Physical

Tungsten is a hard steel-grey metal, often brittle and hard to work in its raw form. However, when very pure, is malleable enough to be worked easily, though it's still very hard. It has the highest melting point of all the metals (3422°C) and second to carbon as the highest melting point of any pure element. Because of this property, it is very difficult to cast, and tungsten objects are often made instead by sintering. Tungsten has the highest tensile strength and lowest coefficient of thermal expansion of any pure metal. Tungsten's density, 19.25 g/cm3 is very close to that of pure gold (19.3 g/cm3), which, along with its other remarkable properties, allows it to be used in jewelry as an alternative to the precious metal.

Availability

Tungsten can be obtained from light bulbs, in the form of filaments. However one would need a very large quantity of light bulbs to obtain a few grams, even thought the metal itself is very dense. About 2-300 incandescent light bulbs will yield like 4-5 grams of tungsten. Tungsten powder can be bought from chemical suppliers, however one should be checking its composition carefully to avoid buying its carbide, as "tungsten powder" is sometimes short for "tungsten carbide powder". It can also be bought as bars as well as wire.

Tungsten metal can also be found in welding rods. Pure tungsten rods are rare but do exist. More often, however, they have small amounts of thorium or a rare earth metal in their composition.

Certain fishing weights are made of tungsten or tungsten alloyed with other heavy metals. These tend to be quite common in California, where tungsten is mined and lead products are sought to be replaced.

Isolation

Elemental tungsten can be prepared by reducing its oxide with carbon or hydrogen. Carbon reduction will generate some tungsten carbide, which will cause the metal to be brittle when sintered. It can also be prepared via thermal decomposition of the hexafluoride or reducing it with hydrogen. The latter method produces a very pure metal.

Projects

  • Making tungsten trioxide
  • Tungsten crucible for growing crystals
  • Synthesizing alkali metal tungstates

Handling

Safety

Tungsten metal, being chemically resistant, is non-toxic. With a few exceptions, most tungsten compounds are relative non-toxic. Inhaled powdered tungsten carbide has been linked to fibrosis, so precautions should be used when working with WC objects.

Storage

No special storage is required for tungsten in bulk form. Powdered tungsten should be stored in closed bottles, away from draft. As it is very dense, use thick or tough containers for storage, as the container might deform when handled too often.

Disposal

Tungsten compounds pose a threat to the environment, so it's best to dispose of them properly.

References

Relevant Sciencemadness threads

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