Electronic data		Thermal data		Steric data
Shells: 2,8,18,18,9,2 Orbitals: [Xe] 5d1 6s2 Electronegativity: 1.1, 1.0 1. Ionization potential: 5.5770 eV 2. Ionization potential: 11.059 eV 3. Ionization potential: 19.174 eV Oxidation states: 3 Electrical conductivity: 0.0126 10^6		Melting point: 918 °C Boiling point: 3464 °C Specific heat: 0.19 J/gK Heat of fusion: 6.20 kJ/mol Heat of vaporization: 414.0 kJ/mol Thermal conductivity: 0.135 W/cmK		Atomic radius: 2.74 Å Ionic radius: 1.16 Å () Covalent radius: 1.69 Å Atomic volume: 20.73 cm³/mol Density (293 K): 6.7 g/cm³ Crystal structure: Hexagonal

Nuclide	Abundance [%]	Mass	Spin	Halflife	Decay mode	Decay tree
137La	0	137	7/2	6E04y	EC	View
138La	0.089	137.907	5	1.05E11y	EC,-	View
139La	99.911	138.906	7/2	--	stable	--
140La	0	140	3	1.678d	-	View
141La	0	141	7/2	3.90h	-	View
142La	0	142	2	1.54m	-	View

Legend

Name origin:	Greek: lanthanein (to be hidden).
Description:	Soft, silvery-white, malleable, ductile metal.
Discovered by:	Carl Mosander
Year:	1839
Place:	Sweden
Sources:	Found with rare earths in monazite and bastnasite. Monazite sand typicall contains 25% lanthanum.
Use(s):	It is used in the electodes of high-intensity, carbon-arc lights. Also used in the production of high-grade europium metal. Because it gives glass refractive properties, it is used in expensive camera lenses.