Chromium, 24Cr |
Chromium |
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Appearance | sillery metallic |
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Standard atomic weight Ar, std(Cr) | 7001519961000000000♠51.9961(6)[1] |
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Chromium in the periodic cairt |
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Atomic nummer (Z) | 24 |
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Group | group 6 |
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Period | period 4 |
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Block | d-block |
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Element category | Transeetion metal |
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Electron confeeguration | [Ar] 3d5 4s1 |
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Electrons per shell | 2, 8, 13, 1 |
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Pheesical properties |
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Phase at STP | solit |
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Meltin pynt | 2180 K (1907 °C, 3465 °F) |
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Bylin pynt | 2944 K (2671 °C, 4840 °F) |
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Density (near r.t.) | 7.19 g/cm3 |
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when liquid (at m.p.) | 6.3 g/cm3 |
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Heat o fusion | 21.0 kJ/mol |
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Heat o vapourisation | 339.5 kJ/mol |
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Molar heat capacity | 23.35 J/(mol·K) |
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Vapour pressur
P (Pa)
|
1
|
10
|
100
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1 k
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10 k
|
100 k
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at T (K)
|
1656
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1807
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1991
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2223
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2530
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2942
|
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Atomic properties |
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Oxidation states | −4, −2, −1, 0, +1, +2, +3, +4, +5, +6 (dependin on the oxidation state, an acidic, basic, or amphoteric oxide) |
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Electronegativity | Pauling scale: 1.66 |
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Ionisation energies | |
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Atomic radius | empirical: 128 pm |
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Covalent radius | 139±5 pm |
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Spectral lines o chromium |
Ither properties |
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Naitural occurrence | primordial |
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Creestal structur | body-centred cubic (bcc) |
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Speed o soond thin rod | 5940 m/s (at 20 °C) |
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Thermal expansion | 4.9 µm/(m·K) (at 25 °C) |
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Thermal conductivity | 93.9 W/(m·K) |
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Electrical resistivity | 125 n Ω·m (at 20 °C) |
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Magnetic orderin | AFM (rather: SDW[2]) |
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Young's modulus | 279 GPa |
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Shear modulus | 115 GPa |
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Bulk modulus | 160 GPa |
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Poisson ratio | 0.21 |
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Mohs haurdness | 8.5 |
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Vickers haurdness | 1060 MPa |
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Brinell haurdness | 1120 MPa |
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CAS Nummer | 7440-47-3 |
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History |
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Diskivery | Louis Nicolas Vauquelin (1797) |
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First isolation | Louis Nicolas Vauquelin (1798) |
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Main isotopes o chromium |
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Decay modes in parentheses are predictit, but hae nae yet been observed |
| references |
style="text-align:left"|
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in
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calc from C
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diff
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report
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ref
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C
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1907
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—
|
—
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|
|
K
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2180
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2180
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0
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|
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F
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3465
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3465
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0
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|
|
WD
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1907 !1907 Celsius
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[3]
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input
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C: 1907, K: 2180, F: 3465
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comment
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style="text-align:left"|
|
|
in
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calc from C
|
diff
|
report
|
ref
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C
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2671
|
—
|
—
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|
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K
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2944
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2944
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0
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F
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4840
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4840
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0
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|
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WD
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4788 !4788 Fahrenheit 2671.9 Celsius 2945 kelvin
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[3]
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input
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C: 2671, K: 2944, F: 4840
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comment
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References
Thir references will appear in the airticle, but this list appears anerly on this page.
- ↑ Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.
- ↑ Fawcett, Eric (1988). "Spin-density-wave antiferromagnetism in chromium". Reviews of Modern Physics. 60: 209. Bibcode:1988RvMP...60..209F. doi:10.1103/RevModPhys.60.209.
- ↑ a b https://www.webelements.com/chromium/.