Lanthanum is a chemical element in the Periodic Table marked with the atomic number of 57 and with the chemical symbol La. This chemical element belongs to period 6 elements and the Lanthanide category. Similar to the rest of the Lanthanide elements Lanthanum possesses metallic properties. In the Periodic Table Lanthanum is preceded by Barium and is followed by Cerium.
In terms and physical and chemical properties Lanthanum shows strong metallic behavior, it is highly reactive, and it gets tarnished when exposed to air. Lanthanum has a 3+ oxidation state and it forms various compounds, which are somewhat unstable. This particular element is actually quite abundant on our planet and it has a large variety of commercial and scientific purposes. It shares several group trends with the rest of the Lanthanum elements and it has the largest atomic radius of them all. Lanthanum is highly reactive to air, cold and hot water, various acids, and other chemical elements. It is somewhat volatile and has a typical hexagonal crystal structure.
Physical Characteristics of Lanthanum
While Lanthanide elements get harder as their atomic number progresses further down the Periodic Table, Lanthanum is actually quite soft. It is variably ductile and brittle and can be easily cut with a knife. The shiny, metallic surface of Lanthanum gets tarnished when its cut or exposed to air. Compared to other Lanthanide elements this particular chemical element is the least volatile one of them. While Lanthanum is a soft element, its resistivity is high. It is weakly paramagnetic and has high melting and boiling points. It appears in a silvery-white color scheme and is quite malleable when compared to other chemical elements in the Periodic Table.
Chemical Properties of Lanthanum
Atomic Number – 57
Group – n/a
Period – 6
Block – f
Electronic Configuration – 5d1 6s2
Relative Atomic Mass – 138.905 (138.90547 g/mol)
Molecular Weight – 138.905
Electronegativity – 1.10
Density (G CM-3) – 6.162 g/cm3 at room temperature; 5.94 g/cm3 in a liquid state
Melting Point – 1193 K; 920 °C; 1688 °F
Boiling Point – 3737 K; 3464 °C; 6267 °F
Atomic Radius – 187pm
Isotopes – 2
Electronic Shell – 2, 8, 18, 18, 9, 2
Discovery of Lanthanum
Lanthanum was recognized not as an actual element, but as a new oxide by a Swedish chemist, named Jöns Jacob Berzelius, in 1803. He worked with an ironmaster, named Vilhelm Hisinger, on the oxide, which they initially named Ceria. As it turned out, Ceria was actually a mixture of various oxides. The Swedish surgeon and chemist Carl Gustav Mosander was the first one to separate the compounds of Lanthanum. In 1839 he used cerium nitrate and nitric acid in order to independently isolate the chemical element. Mosander named the new element after the Ancient Greek term “lanthanein”, which means “to lie hidden”. The very first completely pure isolation of Lanthanum was performed in 1923.
Recognized by: Vilhelm Hisinger and Jöns Jacob Berzelius (1803)
Known and discovered by: Carl Gustav Mosander (1839)
Named by: Carl Gustav Mosander
Uses and role of Lanthanum
This chemical element has a large variety of commercial, industrial and scientific uses. Ever since the 19th century is has played a key role in the manufacturing of gas lantern mantles. Since then present-day science, medicine, biology and other industries have found ways to apply Lanthanum and its compounds to many of their products.
Nowadays Lanthanum finds application in hybrid batteries, hydrogen sponges, electronic vacuum tubes, glass manufacturing, cameras, telescope lenses, infrared optical glass, phosphor lamps, carbon arc lamps, and so on. Lanthanum has many applications in molecular biology, and is even used to purify lake waters from phosphates. It also plays a role in radiometric dating when it comes to estimating the age of various ores and rocks.
Lanthanum on Earth
Compared to other Lanthanide elements Lanthanum is the third most abundant of all of them. It is also quite abundant on Earth when compared to the rest of the chemical elements in the Periodic Table and can be found in our planet’s crust. Pure Lanthanum can be obtained through electrolysis and ion exchange.
Although Lanthanum does not play any biological roles, it has been discovered that it can be useful to modern-day medicine. The human body poorly absorbs this particular element, but the FDA has approved the administering of small Lanthanum dosages in Fosrenol for end-stage renal disease patients as a way to absorb the excess phosphate in their system.