Lanthanum
Name: Lanthanum
Symbol: La
Atomic Number: 57
Mass fraction of the earth’s shell: 43ppm
Melting Point: 920 °C
Boiling Point: 3457 °C
Electrical Conductivity: 1,26 x 106 A·V−1·m−1
Name: Lanthanum
Symbol: La
Atomic Number: 57
Mass fraction of the earth’s shell: 43ppm
Melting Point: 920 °C
Boiling Point: 3457 °C
Electrical Conductivity: 1,26 x 106 A·V−1·m−1
HISTORY
The Swedish chemist Carl-Gustav Mosander achieved a double strike in Stockholm in 1839: in addition to cerium, he also discovered lanthanum in the cerite earth. Since it was literally “hidden” in the cerite, Mosander gave it the name “lanthanum” (from Latin “lanthanein” = hidden).
Mosander thus made a discovery that was soon followed by the finding that other metal oxides – such as samarium, gadolinium, praseodymium, neodymium, and europium – could also be detected in the cerite earth.
CHARACTERISTICS & EXTRACTION
The silvery, shiny lanthanum oxidises in air. With atmospheric humidity, lanthanum hydroxide is formed. Without storage in a protective liquid, it decomposes into powder. At about 400°C air temperature, lanthanum ignites. In cold water, lanthanum is largely unreactive. The rare earth reacts more violently with hot water and diluted acids: it gets warmer, and hydrogen is formed.
Lanthanum is found in flints and is used by the glass industry in the production of high-quality camera lenses.
Monazite sand is indispensable for lanthanum production. To obtain 120 grams of lanthanum, 1 kilogram of monazite sand is needed. Lanthanum fluoride is obtained through a reaction with hydrogen fluoride. Lanthanum is produced after fused-salt electrolysis or reduction with calcium or magnesium.
