Lanthanum

Lanthanum, ₅₇La
Lanthanum
Pronunciation	/ˈlænθənəm/ (LAN-thə-nəm)
Appearance	sillery white
Standard atomic weight Ar, std(La)	138.90547(7)
Lanthanum in the periodic cairt
	barium ← lanthanum → cerium
Atomic nummer (Z)	57
Group	group 3
Period	period 6
Block	f-block
Element category	Lanthanide
Electron confeeguration	[Xe] 5d1 6s2
Electrons per shell	2, 8, 18, 18, 9, 2
Pheesical properties
Phase at STP	solit
Meltin pynt	1193 K (920 °C, 1688 °F)
Bylin pynt	3737 K (3464 °C, 6267 °F)
Density (near r.t.)	6.162 g/cm3
when liquid (at m.p.)	5.94 g/cm3
Heat o fusion	6.20 kJ/mol
Heat o vapourisation	402.1 kJ/mol
Molar heat capacity	27.11 J/(mol·K)
Atomic properties
Oxidation states	0, +1, +2, +3 strangly basic
Electronegativity	Pauling scale: 1.10
Atomic radius	empirical: 187 pm
Covalent radius	207±8 pm
	Colour lines in a spectral rangeSpectral lines o lanthanum
Ither properties
Naitural occurrence	primordial
Creestal structur	hexagonal
Speed o soond thin rod	2475 m/s (at 20 °C)
Thermal expansion	(r.t.) (α, poly) 12.1 µm/(m·K)
Thermal conductivity	13.4 W/(m·K)
Electrical resistivity	(r.t.) (α, poly) 615 n Ω·m
Magnetic orderin	paramagnetic
Young's modulus	(α form) 36.6 GPa
Shear modulus	(α form) 14.3 GPa
Bulk modulus	(α form) 27.9 GPa
Poisson ratio	(α form) 0.280
Mohs haurdness	2.5
Vickers haurdness	491 MPa
Brinell haurdness	363 MPa
CAS Nummer	7439-91-0
History
Diskivery	Carl Gustaf Mosander (1838)
Main isotopes o lanthanum
β−	138Ce
	Decay modes in parentheses are predicted, but hisna yet been observed
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Lanthanum is a chemical element wi the seembol La an atomic nummer 57. Lanthanum is a siller white metallic element an is the first element o the lanthanide series. It is foond in some rare-yird minerals, uisually in combination wi cerium an ither rare yird elements. Lanthanum is a malleable, ductile, an saft metal that oxidises rapidly whan exposed tae air. It is produced frae the minerals monazite an bastnäsite uisin a complex multistage extraction process. Lanthanum compoonds hae hantle applications as catalysts, additives in gless, carbon lichtin for studio lichtin an projection, igneetion elements in lichters an torches, electron cathodes, scintillators, an ithers. Lanthanum carbonate (La₂(CO₃)₃) haes been approved as a medicine for treatin renal failur.

References

↑ 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.
↑ Yttrium and all lanthanides except Ce, Pm, Eu, Tm, Yb have been observed in the oxidation state 0 in bis(1,3,5-tri-t-butylbenzene) complexes, see Cloke, F. Geoffrey N. (1993). "Zero Oxidation State Compounds of Scandium, Yttrium, and the Lanthanides". Chem. Soc. Rev. 22: 17–24. doi:10.1039/CS9932200017.
↑ Magnetic susceptibility of the elements and inorganic compounds, in Handbook of Chemistry and Physics (PDF). CRC press. 2000. ISBN 0849304814.

[CIAAW2013-1] 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.

[Cloke1993-2] Yttrium and all lanthanides except Ce, Pm, Eu, Tm, Yb have been observed in the oxidation state 0 in bis(1,3,5-tri-t-butylbenzene) complexes, see Cloke, F. Geoffrey N. (1993). "Zero Oxidation State Compounds of Scandium, Yttrium, and the Lanthanides". Chem. Soc. Rev. 22: 17–24. doi:10.1039/CS9932200017.

[magnet-3] Magnetic susceptibility of the elements and inorganic compounds, in Handbook of Chemistry and Physics (PDF). CRC press. 2000. ISBN 0849304814.

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