What is Lanthanum

Lanthanum (pronunciation: LAN-the-nem) ^[3] is a soft, silvery rare-earth metal belonging to the lanthanoids family and represented by the chemical symbol La ^{[1, 2]}. Its main isotopes include the most abundant ¹³⁹La (with 99.91% natural abundance) and the most stable ¹³⁸La, the radioactive isotope with a half-life period of 1.06 X 10²⁶ years ^{[1, 4]}.

Where can Lanthanum be Found

The element naturally occurs in bastnaesite and monazite, making up 38% and 25% of the rare-earth minerals respectively ^[1]. Isolation of lanthanum from these minerals involves solvent extraction and ion-exchange separation techniques ^[1]. The metal can be produced through calcium reduction of anhydrous fluoride ^[1]. The top 3 lanthanum producing countries include China, Russia, and Malaysia while the top 3 countries with the largest lanthanum reserves are China, CIS Countries, and the USA ^[1].

History

Origin of its Name: The name of the element is derived from the Greek word ‘lanthanein’, which means to lie hidden, as its existence in cerium oxide was long undetected ^[1].

Who discovered it: The Swedish chemist Carl Gustaf Mosander is credited with the discovery of lanthanum ^[1].

When and How was it Discovered

In January 1839, lanthanum was extracted by Carl Mosander while working on his sample of cerium at the Karolinska Institute in Sweden ^[1]. He took powdered cerium nitrate and treated it with dilute nitric acid ^[5]. He observed that some of the nitrate powder dissolved in the acid, and then he decided to isolate the mixture from the precipitate by using heat and sodium oxalate ^[5]. The pale brick-colored oxide obtained was given the name lanthana ^{[3, 5]}.

A student at the Karolinska Institute, Axel Erdmann discovered the element independently from a new mineral found in a Norwegian fjord ^{[1, 5]}. The new mineral was named mosandrite after Carl Mosander who produced impure lanthanum from anhydrous cerium chloride ^[5]. In 1923, pure lanthanum was obtained by Kremers and Stevens through electrolysis of fused halides ^[5].

Lanthanum Identification
Atomic number	57 [1]
CAS number	7439-91-0 [1]
Position in the periodic table	Group	Period	Block
	Lanthanides [1]	6 [1]	d [1]

Properties and Characteristics of Lanthanum

Atomic Data of Lanthanum (Element 57)

What is Lanthanum Used for

Although lanthanum metal is not commercially used, its alloys may have some uses ^[1]:

• An alloy of lanthanum and nickel is used for hydrogen storage in hydrogen-fueled vehicles ^[1]. It is used in large amounts in the anode (positively charged electrode) of NiMH (nickel metal hydride) batteries that are found in hybrid cars ^{[1, 5]}.
• Lanthanum is a constituent element in misch metal (an alloy of rare earth metals) that is used in flints for producing igniting sparks in cigarette lighters ^[1].
• Compounds with lanthanum are extensively used in cinema projection, studio lighting, and other carbon lighting applications ^[1].
• Lanthanum (III) oxide (La₂O₃) is used in producing high-quality optical glasses, telescope and camera lenses because it has low dispersion, high refractive index, and it imparts high alkali resistance ^{[1, 5]}, producing a clear, sharp image.
• It is used as a catalyst in petroleum industries for cracking the long chain hydrocarbons ^[5].
• Ionic lanthanum (La3+) is used as a tracer and marker of Ca2+ spikes in blood, and studies have shown that radioactive lanthanum and its compounds may be used in treating cancer ^[1].
• Lanthanum carbonate (fosrenol) is useful for reducing phosphate levels in people affected by kidney disease ^[5].

Possible Health Effects

Lanthanum and its compounds, although not known to play any biological role in humans, can be a little or moderately toxic and should be handled with caution and proper protection ^[1].

Interesting Facts

• The element rapidly oxidizes in air and is easily burned when ignited ^[1].
• It is sometimes visually represented with an image of a camera lens in reference to its use in cameras ^[1].

How much does Lanthanum Cost

The price of 100 grams of pure lanthanum is around $800 while its price in bulk ranges between $6,000 and $6,500 ^{[5, 8]}.

References
1. http://www.rsc.org/periodic-table/element/57/lanthanum
2. https://pubchem.ncbi.nlm.nih.gov/compound/lanthanum#section=Top
3. https://education.jlab.org/itselemental/ele057.html
4. https://www.webelements.com/lanthanum/isotopes.html
5. https://www.chemicool.com/elements/lanthanum.html
6. http://periodictable.com/Elements/057/data.html
7. http://chemistry-reference.com/q_elements.asp?language=en&Symbol=La
8. http://hobart.k12.in.us/ksms/PeriodicTable/lanthanum.htm