Lanthanum, La

Lanthanum is a chemical element with the symbol La and atomic number 57.

Lanthanum is a silvery white metallic element that belongs to group 3 of the periodic table and is a lanthanide. Found in some rare-earth minerals, usually in combination with cerium and other rare earth elements. Lanthanum is malleable, ductile, and soft enough to be cut with a knife. It is one of the most reactive of the rare-earth metals. The metal reacts directly with elemental carbon, nitrogen, boron, selenium, silicon, phosphorus, sulfur, and with halogens. It oxidizes rapidly when exposed to air. Cold water attacks lanthanum slowly, while hot water attacks it much more rapidly.

Technical Data
Symbol La Density (20°C)/gcm3 6.17
Atomic number 57 Melting point / °C 920
No. of naturally occurring isotopes 2 Boiling point / °C 3420
Atomic weight 138.9055 ΔHfus/kJmol-1 8.5
Electronic configuration [Xe]5d16s2 ΔHvap/kJmol-1 402
Metal radius( 12-coordinate)/pm 187 ΔHf(monoatomic gas/kJmol-1 423(+/-6)
Ionic radius(6-coordinate)/pm 103.2 Electronegativity χ 1.1
Ionization energy Idmol-1 I 538 Electrical resistisvity  
Ionization energy/kJmol-1 II 1067 (20°C)/μohm cm 57-80
Ionization energy/kJmol-1 III 1850 Eo(M3+(aq)+ 3e- →M(S))/V -2.522
Evaporation Techniques
Temperature (oC) @Vap. Pressure Techniques Remarks
10-8 Torr 10-6 Torr 10-4 Torr Electron Beam Crucible Coil Boat
990 1212 1388 Excellent Al2O3 - Tungsten & Tantalum Films will burn in air if scraped

Evaporation Materials
L1-5000-M 3-6mm pieces
L1-5001-M Ingot (Please ask for sizes)
L1-5012-M pieces 12mm and smaller

The foils are available in either rectangular or circular shape. Please enter width and length or diameter of the required foil.

Foil
L1-3003-F 0.004" (0.1mm)
L1-3007-F 0.008" (0.2mm)
Rods
L1-2000-R 0.250" (6.35mm)
L1-2001-R 0.500" (12.7mm)
Sheet
L1-4002-S 0.020" (0.5mm)
L1-4003-S 0.030" (0.76mm)
L1-4004-S 0.040" (1mm)