మూస:Infobox lanthanum

లాంథనం, ₀₀La
లాంథనం
Pronunciation	/ˈlænθənəm/ (LAN-thə-nəm)
Appearance	silvery white
Standard atomic weight Ar°(La)
	138.90547±0.00007; 138.91±0.01 (abridged);
లాంథనం in the periodic table
Group	f-block groups (no number)
Period	period 6
Block
Electrons per shell	2, 8, 18, 18, 9, 2
Physical properties
Phase at STP	solid
Melting point	1193 K (920 °C, 1688 °F)
Boiling point	3737 K (3464 °C, 6267 °F)
Density (near r.t.)	6.162 g/cm3
when liquid (at m.p.)	5.94 g/cm3
Heat of fusion	6.20 kJ/mol
Heat of vaporization	402.1 kJ/mol
Molar heat capacity	27.11 J/(mol·K)
Atomic properties
Oxidation states	0, +1, +2, +3 (a strongly basic oxide)
Electronegativity	Pauling scale: 1.10
Atomic radius	empirical: 187 pm
Covalent radius	207±8 pm
Other properties
Natural occurrence	[[Primordial nuclide\|primordial]]
Crystal structure	hexagonal
Speed of sound 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 ordering	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 hardness	2.5
Vickers hardness	491 MPa
Brinell hardness	363 MPa
CAS Number	7439-91-0
History
Discovery	Carl Gustaf Mosander (1838)
Isotopes of లాంథనం v; e;
	Template:infobox లాంథనం isotopes does not exist
	Category: లాంథనం; view; talk; edit; \| references

References

↑ "Standard Atomic Weights: Lanthanum". CIAAW. 2005.
↑ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; et al. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry (in ఇంగ్లీష్). doi:10.1515/pac-2019-0603. ISSN 1365-3075.
↑ Yttrium and all lanthanides except Ce and Pm 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. and Arnold, Polly L.; Petrukhina, Marina A.; Bochenkov, Vladimir E.; Shabatina, Tatyana I.; Zagorskii, Vyacheslav V.; Cloke (2003-12-15). "Arene complexation of Sm, Eu, Tm and Yb atoms: a variable temperature spectroscopic investigation". Journal of Organometallic Chemistry. 688 (1–2): 49–55. doi:10.1016/j.jorganchem.2003.08.028.
↑ La(I), Pr(I), Tb(I), Tm(I), and Yb(I) have been observed in MB₈⁻ clusters; see Li, Wan-Lu; Chen, Teng-Teng; Chen, Wei-Jia; Li, Jun; Wang, Lai-Sheng (2021). "Monovalent lanthanide(I) in borozene complexes". Nature Communications. 12 (1): 6467. doi:10.1038/s41467-021-26785-9. PMC 8578558. PMID 34753931.
↑ Magnetic susceptibility of the elements and inorganic compounds, in Handbook of Chemistry and Physics (PDF). CRC press. 2000. ISBN 0849304814.