Nepedia
Back to Discover
Advanced Reader
⚛️

Sodium borohydride

physical science Maturity 11-13 Next article →

Sodium borohydride is an inorganic compound used widely in chemistry and industry. It is a white to gray-white microcrystalline powder that often forms lumps. Chemically, it is known as sodium tetrahydridoborate or sodium tetrahydroborate. Its chemical formula is NaBH4. This substance acts as a powerful reducing agent. A reducing agent is a chemical that helps transform one substance into another by adding electrons or hydrogen. Because of this ability, it is essential for making medicines, paper, and dyes.

The compound functions through a process called reduction. In a laboratory setting, it is most commonly used to convert ketones and aldehydes into alcohols. This chemical change happens in two distinct stages. First, the reaction forms an intermediate called an alkoxide. Second, a process called hydrolysis occurs to complete the transformation. Sodium borohydride can also reduce acyl chlorides, anhydrides, and imines at room temperature or even lower. However, it is less efficient with esters and cannot reduce carboxylic acids or amides at all.

Sodium borohydride has a specific internal structure. It is a salt made of a tetrahedral anion. The solid exists in three different forms, called polymorphs: alpha, beta, and gamma. The alpha phase is the most stable at room temperature and pressure. It has a cubic structure similar to sodium chloride (NaCl). If you increase the pressure to 6.3 GPa, the structure changes to a tetragonal beta phase. At an even higher pressure of 8.9 GPa, the orthorhombic gamma phase becomes the most stable.

Scientists discovered this compound during the 1940s. Hermann I. Schlesinger led a research team that was actually searching for volatile uranium compounds. In 1945, Schlesinger and Herbert C. Brown published work on preparing alkali metal compounds. Because this research took place during wartime, the results were kept secret for a time. The findings were finally declassified and made public in 1953. This discovery opened new doors for organic synthesis and industrial chemistry.

Factories produce millions of kilograms of sodium borohydride every year. This amount far exceeds the production of any other hydride reducing agent. One major method for making it is the Brown-Schlesinger process. In this method, sodium hydride reacts with trimethyl borate at temperatures between 250 and 270 degrees Celsius. Another method is the Bayer process. This process uses inorganic borates like borax or borosilicate glass. It involves treating these borates with alkali metal hydrides at temperatures above 100 degrees Celsius.

This compound has many important uses in our daily lives. Its largest application is in paper manufacturing. It is used to produce sodium dithionite from sulfur dioxide. Sodium dithionite is a vital bleaching agent for wood pulp and the dye industry. Sodium borohydride is also a key tool in making medicines. It helps synthesize antibiotics like chloramphenicol and dihydrostreptomycin. It is also used in the production of steroids and vitamin A.

Researchers are also exploring new ways to use sodium borohydride. It has been studied as a way to store hydrogen for fuel-powered vehicles. It is stable in dry air, which makes it safer than many other hydrogen storage options. In 2012, scientists used a special nanostructure to store and release hydrogen under moderate conditions. Additionally, it has been tested as a green rocket propellant at Purdue University. While some of these uses are still in the research phase, they show how versatile this chemical can be.

558 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

More to explore

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.