లాంథనం, 00 La Pronunciation (LAN-thə -nəm ) Appearance silvery white
Group మూస:Infobox element/symbol-to-group/format Period period 6 Block f-block Electron configuration [Xe ] 5d1 6s2 Electrons per shell 2, 8, 18, 18, 9, 2 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) Vapor pressure (extrapolated)
P (Pa)
1
10
100
1 k
10 k
100 k
at T (K)
2005
2208
2458
2772
3178
3726
Oxidation state s0,[ 3] +1,[ 4] +2, +3 (a strongly basic oxide) Electronegativity Pauling scale: 1.10 Atomic radius empirical: 187 pm Covalent radius 207±8 pm Spectral line s of లాంథనంNatural occurrence 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 [ 5] 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 Discovery Carl Gustaf Mosander (1838) Template:infobox లాంథనం isotopes does not exist Category: లాంథనం | references
References
These references will appear in the article, but this list appears only on this page.
↑ "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 .