General | States | Energies | Oxidation & Electrons |Appearance & Characteristics
Reactions | Other Forms |Radius | Conductivity | Abundance
Encyclopedia Britannica articles


Name Lanthanum Symbol La
atomic number 57 Atomic weight 138.9055
Density @ 293 K 6.7 g/cm3 Atomic volume 20.73 cm3/mol
Group Trans. Met. discovered 1839


state (s, l, g) s
melting point 1193.2 K boiling point 3693 K
Heat of fusion 6.20 kJ/mol Heat of vaporization 414.0 kJ/mol
Back to the top


1st ionization energy 538.1 kJ/mole electronegativity 1.1
2nd ionization energy 1067 kJ/mole electron affinity 50 kJ/mole
3rd ionization energy 1850 kJ/mole Specific heat 0.19 J/gK
heat atomization 423 kJ/mole atoms

Oxidation & Electrons

Shells 2,8,18,18,9,2 electron configuration [Xe] 5d1 6s2
minimum oxidation number 0 maximum oxidation number 3
min. common oxidation no. 0 max. common oxidation no. 3
Back to the top

Appearance & Characteristics

structure cp: close packed (ABCB) color silvery-white
uses lighter flints, CRTs toxicity
hardness mohs characteristics soft, malleable


reaction with air vigorous, w/ht = La2O3 reaction with 6M HCl mild, = H2, LaCl3
reaction with 6M HCl mild, = H2, LaCl3 reaction with 15M HNO3 mild, = La(NO3)3
reaction with 6M NaOH
Back to the top

Other Forms

number of isotopes 2 hydride(s) LaH2 LaH3
oxide(s) La2O3 chloride(s) LaCl3


ionic radius (2- ion) pm ionic radius (1- ion) pm
atomic radius 187 pm ionic radius (1+ ion) pm
ionic radius (2+ ion) pm ionic radius (3+ ion) 117.2 pm
Back to the top


thermal conductivity 13.4 J/m-sec-deg electrical conductivity 14.2 1/mohm-cm
polarizability 31.1 A^3


source Monazite(phosphate),bastnaesite rel. abund. solar system -0.351 log
abundance earth's crust 1.5 log cost, pure 64 $/100g
cost, bulk $/100g
Back to the top

World Wide Web presentation of Chemicool Periodic Table is © Copyright 1996-99 by David D. Hsu. Some data were provided by and used with the permission of JCE Software and is owned and copyright by the Division of Chemical Education, Inc. Additional data were provided by Perkin-Elmer through Peter Lykos of IIT. The information may not be redistributed without the permission of David Hsu or JCE Software.