Periodic table

 

 

Atomic number:57

Group numbers:3

Period:6

Electronic configuration:[Xe] 5d¹ 6s²

Formal oxidation number:+3

Electronegativities:1.1

Atomic radius / pm:187

Relative atomic mass:138.90547 ± 0.00007

 

Lanthanum was discovered by Carl Gustaf Mosander (SE) in 1839. The origin of the name comes from the Greek word lanthanein meaning to lie hidden. It is a soft, silvery-white, malleable, ductile metal that tarnishes readily in air and reacts with oxidants. Reaction with water releases hydrogen gas, metal ignites and burns readily. Lanthanum is found with rare earths in monazite and bastnasite. Monazite sand typical contains 25% lanthanum. It is used in the electrodes of high-intensity, carbon-arc lights. Because it gives glass refractive properties, it is used in expensive camera lenses.

PHYSICAL PROPERTIES

Density / g dm^-3:6145 (298 K)

Molar volume / cm³mol^-1:22.60 (298 K)

Electrical resistivity / μΩcm:57 (20 °C)

THERMAL PROPERTIES

Thermal conductivity / W m^-1K^-1:13.5

Melting point / °C:918

Boiling point / °C:3464

Heat of fusion / kJ mol^-1:10.04

Heat of vaporization / kJ mol^-1:402.1

Heat of atomization / kJ mol^-1:431.29

IONIZATION ENERGIES

First ionization energy / kJ mol^-1:538.10

Second ionization energy / kJ mol^-1:1067.14

Third ionization energy / kJ mol^-1:1850.34

ABUNDANCE OF ELEMENTS

in the atmosphere / ppm:-

in the Earth's crust / ppm:16

in the oceans / ppm:0.0003

CRYSTALLOGRAPHIC DATA

ISOTOPES

REDUCTION POTENTIALS

 

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Citing this page:

Generalic, Eni. "Lanthanum." EniG. Periodic Table of the Elements. 3 Jan. 2012. KTF-Split. {Date of access}. <http://www.periodni.com/la.html>.