Praseodymium is a chemical element that exhibits metallic properties. In chemistry, it is identified with the symbol 'Pr'. It is classified as a rare earth element, and it belongs to the lanthanide series of the periodic table.
The credit for the discovery of praseodymium goes to the renowned Austrian chemist, Carl F. Auer von Welsbach. He was working with a substance named didymium, which at that time, was considered as a metallic element. In 1885, he discovered that didymium is not one single element, but is actually composed of two rare earth elements: neodymium and praseodymium. When he isolated praseodymium, he found it in the form of a green powder. The name praseodymium, was hence derived from the Greek words prasios, which means green, and didymos, which means twin.
There are a wide variety of mineral compounds found in nature which contain praseodymium. Among them, monazite and bastnasite are two of its main natural sources. It is extracted from these minerals with the help of a solvent extraction method, or ion-exchange method. As these ores have radioactive elements like thorium in them, lots of precautionary measures are required while handling these ores during extraction of this metal. The pure form of praseodymium can also be produced artificially.
In its pure form, praseodymium is identified as a soft metal, which is silvery-white in color. However, on exposure to air, it gets corroded easily and a green tarnish appears on its surface. To maintain its original color and characteristics, this metal is often stored in mineral oil, or sealed containers. Like other metals, it is very ductile and malleable in nature.
The atomic number of praseodymium is 59. There are nine different isotopes of praseodymium found in nature, and among them, praseodymium 141 is the most stable one. Besides these, there are several man-made isotopes. To this date, its recognized isotopes are as many as 38. Most of its compounds are black in color, with a tinge of green or yellow in them.
Some of the most common uses of praseodymium are as follows:
- It is a component of an alloy named misch metal, which is used during the manufacturing of cigarette lighters.
- It is used as an alloying agent in other stronger metal alloys, that are being specially used for the manufacturing of aircraft engines. In these alloys, it is mostly used along with magnesium.
- All oxides of praseodymium have excellent refractory properties. For this reason, along with other rare earth metals, it is part of the core material of carbon arc lights, which are popularly used in the movie industry for the purpose of projection and studio lighting.
- Salts of praseodymium have a major role to play in the glass and enamel industry. Here, it is used with a few other substances in order to add an intense yellow color to the manufactured glasses and enamels.
- It is also used as a colorant in the making of a special type of glass named didymium glass. This particular glass is required for making goggles used by welders and glass blowers.
- Usually, neodymium is used in magnets. Sometimes however, neodymium is replaced by praseodymium, as it is more affordable.
- It is added to synthetic cubic zirconia, in order to obtain a yellowish-green color. This colored stone is then used for making jewelry.
- Apart from various industrial applications, this element has some laboratory applications as well. It is alloyed with nickel, and then used for conducting various important laboratory experiments.
In general, its toxicity ranges from mild to moderate. However, inhalation of its dust or fumes, could be hazardous to health. Therefore, when it is handled during its various commercial uses, suitable safety measures are a must.