Introduction
Holmium is a chemical element with the atomic number 67 and the symbol Ho. It is a rare earth element and a member of the lanthanide series. It was discovered in 1878 by Swedish chemist Per Theodor Cleve and is named after the village of Holmia, which was the Latin name for Stockholm.
Physical Properties
Holmium is a silvery-white, lustrous, and relatively soft metal. It has a high density, with a value of 8.79 g/cm³, which is higher than most other metals. It has a melting point of 1,470°C and a boiling point of 2,700°C. Holmium is a paramagnetic metal, meaning it is weakly attracted to a magnetic field.
Chemical Properties
Holmium is highly reactive and readily loses two electrons to form a +3 ion. It is also highly electropositive, which means it readily loses electrons to form a positive ion. Holmium is highly reactive with water, and when it comes into contact with it, it forms a white oxide. It also reacts with acids, such as hydrochloric acid and sulfuric acid, to form halides and oxides.
Occurrence and Production
Holmium is a relatively rare element and is found in small amounts in many minerals, including monazite, xenotime, and euxenite. It is also found in smaller amounts in some iron and manganese ores. The primary source of holmium is the monazite mineral, which is found in China, India, and the United States. Holmium is typically extracted from these minerals through a process known as solvent extraction, which involves dissolving the mineral in a solvent and then separating the holmium from other elements.
Applications
Holmium has several practical applications due to its unique properties. One of its most notable applications is in the production of lasers. Holmium ions are used in solid-state lasers, which are commonly used in medical applications, such as cutting and welding. Holmium is also used in the production of high-temperature superconductors, which are used in applications such as medical imaging and magnetic resonance imaging (MRI). Additionally, holmium is used in the production of catalysts, which are used in the petroleum industry to increase the efficiency of chemical reactions.
Compounds
Holmium has several compounds that are used in various applications. One of the most notable compounds is holmium oxide (Ho2O3), which is used as a catalyst in the production of polyethylene and polypropylene. Another compound is holmium chloride (HoCl3), which is used as a catalyst in the production of vinyl chloride. Holmium also has several rare earth compounds that are used in the production of phosphors, which are used in applications such as fluorescent lighting and television screens.
Safety and Handling
Holmium is a highly reactive element that requires careful handling and storage. It is a fire hazard when it comes into contact with air, and it can also ignite spontaneously when it comes into contact with certain materials. When handling holmium, it is essential to wear protective gloves, safety glasses, and a face mask to prevent exposure to its toxic fumes. Holmium should also be stored in a cool, dry place, away from any sources of ignition.
References
- National Institute of Standards and Technology. (2020). Holmium.
- Royal Society of Chemistry. (2020). Holmium.
- CRC Handbook of Chemistry and Physics. (2020). Holmium.
- Holmium. (2020). In Encyclopedia Britannica.