Lanthanum, 57La |
General properties |
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Pronunciation | Template:Infobox element/pronunciation |
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Appearance | silvery white |
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Standard atomic weight (Ar, standard) | Template:Infobox element/standard atomic weight |
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Mass number | Template:Infobox element/symbol-to-most-stable-isotope (most stable isotope) |
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Lanthanum in the periodic table |
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Template:Infobox element/periodic table |
Atomic number (Z) | 57 |
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Group | Template:Infobox element/group |
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Period | period 6 |
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Block | d-block |
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Element category | Template:Infobox element/category format, sometimes considered a transition metal |
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Electron configuration | [Xe] 5d1 6s2 |
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Electrons per shell | 2, 8, 18, 18, 9, 2 |
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Physical properties |
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Phase at STP | solid |
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Melting point | 1193 K (920 °C, 1688 °F) |
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Boiling point | 3737 K (3464 °C, 6267 °F) |
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Density (near r.t.) | 6.162 g/cm3 |
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when liquid (at m.p.) | 5.94 g/cm3 |
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Heat of fusion | 6.20 kJ/mol |
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[[Enthalpy of vaporization|Heat of Template:Engvar]] | 400 kJ/mol |
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Molar heat capacity | 27.11 J/(mol·K) |
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[[Vapor pressure|Template:Engvar pressure]] (extrapolated) |
Atomic properties |
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Oxidation states | Template:Infobox element/symbol-to-oxidation-state |
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Electronegativity | Pauling scale: 1.10 |
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[[Ionization energy|Template:Engvar energies]] | - 1st: 538.1 kJ/mol
- 2nd: 1067 kJ/mol
- 3rd: 1850.3 kJ/mol
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Atomic radius | empirical: 187 pm |
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Covalent radius | 207±8 pm |
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Template:Infobox element/spectral lines |
Other properties |
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Crystal structure | Template:Infobox element/crystal structure |
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Speed of sound thin rod | 2475 m/s (at 20 °C) |
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Thermal expansion | α, poly: 12.1 µm/(m·K) (at r.t.) |
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Thermal conductivity | 13.4 W/(m·K) |
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Electrical resistivity | α, poly: 615 nΩ·m (at r.t.) |
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Magnetic ordering | paramagnetic[1] |
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Magnetic susceptibility | +118.0·10−6 cm3/mol (298 K)[2] |
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Young's modulus | α form: 36.6 GPa |
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Shear modulus | α form: 14.3 GPa |
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Bulk modulus | α form: 27.9 GPa |
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Poisson ratio | α form: 0.280 |
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Mohs hardness | 2.5 |
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Vickers hardness | 360–1750 MPa |
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Brinell hardness | 350–400 MPa |
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CAS Number | 7439-91-0 |
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History |
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Discovery | Carl Gustaf Mosander (1838) |
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Main isotopes of lanthanum |
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Template:Infobox element/isotopes table |
| references |
Template:Infobox element/element navigation
Template:Template reference list
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