Chemicool

La

57

138.9055
Lanthanum
General | States | Energies | Oxidation & Electrons |Appearance & Characteristics
Reactions | Other Forms |Radius | Conductivity | Abundance
Encyclopedia Britannica articles

General
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

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

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

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

Abundance
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
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