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	ΔH_fus/kJmol^-1	8.5
Electronic configuration	[Xe]5d¹6s²	ΔH_vap/kJmol^-1	402
Metal radius( 12-coordinate)/pm	187	ΔH_{f(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	E^o(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	Remarks
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)

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